Air travel used to be very awesome. You even dressed up in a suit and tie just to sit in a metal tube! Now, for many passengers, it's a pain in the ass. What happened?
The short answer is probably what you're expecting: $$$
When air travel started to become a thing, it was as much a luxury product as it was a means of transportation. Aircraft were expensive, safety features and creature comforts were expensive (and yet air travel was still dangerous and uncomfortable) and the infrastructure was very expensive. Compounding this was the fact that the average airliner of the 1920s or 1930s (we're talking about fixed-gear, often still tube-and-fabric, often still biplane aircraft all the way up to WWII even) typically had enough room and power to carry only a dozen passengers or less, or an exceptionally large and powerful airliner might carry 20 or 30 passengers. The Douglas DC-3, arguably the most advanced airliner on the eve of WWII, could still only carry two dozen passengers or so in any accommodations remotely resembling comfort, and only a relatively small handful were built before the type was commandeered for war production as the C-47. This meant there was no way the economy of scale could be there at the time. Even with sizable government subsidies, the cost simply had to be passed down to the consumer. When you're catering to an elite set to begin with, you damn better well make sure it's glamorous, or at least looks glamorous.
Fast forward to the start of the jet age. The Boeing 707 was coming on-line, the largest, fastest, most advanced airliner realistically conceived up to that point (with several similar, competing products in the pipeline too); safety regulations and gear made air travel much, much less risky, and the infrastructure was more than up to snuff thanks to a combination of development during WWII and continued civilian development in a new, booming age of globalization. One very important thing, however, didn't change - the government subsidies that were in place since the birth of American commercial aviation in an effort to foster technological and commercial innovation in air travel. Specifically, the Civilian Aviation Authority - and later its successor, the Federal Aviation Administration (a sub-branch of the Department of Transportation) doled out very stipulating airway rights and air route privileges to select airlines. This enforced a de facto no compete clause across the entire U.S. airline network - United Airlines, for example, didn't have to worry about much competition from Delta Air Lines because the two didn't compete with each other in the same geographic area. Northwest Airlines held most of the air route privileges to - you guessed it - the Northwest (including significant advantageous airway rights to Korea and Japan - especially important in the 50s and 60s). Eastern Airlines - get ready for this - held most of its operations in the East - which once again proved extremely popular and trouble-free as they had a lot of free reign not only on the eastern seaboard but on-wards to London, Paris, Berlin and Rome. Pan Am also had air route rights to much of the East - but more importantly, had a virtual monopoly on many foreign air travel routes, especially to the then-huge South American market, effectively making Pan Am the United States' de facto flag carrier (i.e., a really huge deal).
To explain the thinking behind this, let's take a detour towards a more Jalopnik-related analogy. Did you know there were hundreds upon hundreds of car manufacturers from the time R.E. Olds tested his first car to the time Jeeps started rolling off Ford lines? Even in the 1920s, before the Great Depression, many of these car companies started to disappear due to a glut of competition. Needless to say in 1935 things started looking very ugly, and things quickly streamlined to the Big 6 (Ford, GM, Chrysler, Hudson, Packard, Studebaker) - then the Big 5 as Packard and Studebaker combined - then the Big 4 when Hudson joined in to make AMC - and you know the rest. The airline industry was no different - hundreds of local operations started to spring up. The government had a keen interest to subsidize air travel in order to advance its development and safety, but wasn't very interested in subsidizing hundreds of airlines, the vast majority of which would inevitably fail anyway. So to make things simple, the CAA picked the airlines it thought were most likely to succeed (usually the largest, like Delta, United and especially Pan Am), gave them exclusive airway rights, and told everyone else to pack up and go home. From that point on, any new prospective airline had to get CAA/FAA approval to go from business draft to operational - and until the end of WWII, that was near-impossible. The only real loophole was that airlines could operate "unrestricted" in a very small geographical space, which meant the vast majority of what was left were very small operations. There was one very important exception to this - one airline figured out that there were enough very large population centers just within that geographic distance, specifically in California and Texas, to make business sense without going through the near-impossible FAA approval process. That airline is Southwest, and explains the origin of their "point-to-point" business model.
But let's go back to the birth of the Jet Age. These were golden times for the airlines - so much so, that the FAA actually did approve a relatively large number of new operations to start up, mainly to act as feeder lines for the Big Boys. The lack of mutual competition meant that the airlines can still market based on the glamour factor. And who the hell else was even going to bother to travel to Japan, Europe or South America other than a suit-and-tie businessman, or a well-heeled leisure traveler? There wasn't a pressing need to cram everybody in the plane like sardines in order to maximize the scales of economy. Airliner manufacturers like Boeing, Lockheed and Douglas marketed their planes based on comfort and seat pitch - look how much legroom you're going to get in a 707! The Lockheed L-1011 was marketed for its ability to have a lounge area where some baggage hold space would normally be - an option that was actually picked up by Pacific Southwest Airlines. This was also the age when it looked like supersonic airliners would make sense, once again selling speed rather than economy, because the economic incentive wasn't present in the regulation era. The British tried developing a piston-powered airliner right after WWII called the Brabazon (named after Baron Brabazon, who lead a committee pushing postwar British aeronautical development) and it was rejected because it was thought to be too large.
Roughly the size of an early 707, it could easily carry more than the 100 passengers it was planned for, but nobody dared thought to cram any more seats in because comfort was king.
So what changed all this? Mostly, it was the work of a single man. A very important, very politically influential man:
Well, more specifically, it was the result of a prelude to various things that would accumulate into what's now known as the Reagan Revolution. Even moreover, it was the result of a lot of people who wanted to start their own airlines that made a lot of business sense, but would never get approval in the regulation era thanks to those de facto non-compete clauses. Finally, the purpose for all that regulation was now becoming obsolete - the pace of technological and safety development had outstripped what the government can subsidize, so many people felt the regulation era was merely keeping things stagnant and preventing competition. So in the late 70s (still under President Carter's watch), the first overtures towards deregulation were made.
Perhaps the biggest game changer from the birth of the deregulation era was the LCC - the Low-Cost Carrier. Remember Southwest, the little airline the skirted regulation by remaining confined to their small geographic area? They were now able to expand their business model to the entire country, and expand they did. Other airlines copied their business model - JetBlue, Frontier, what would later become AirTran and Midwest, and many, many others, most of which would, like in the 20s and 30s, fail. The immediate effect was that the LCCs would live up to their name - they would compete against the big boys on price point. They achieved this in large part by simply reducing their infrastructure need - they were cheaper in simply being smaller. Because they never flew overseas, flew small planes and in most cases (such as with Southwest) only flew a single airplane type, they could get away with cheaper infrastructure without compromising comfort or especially safety. Many of these airlines (once again, including Southwest) also flew into airports that were under-served by the bigger airlines; in many of these cases, the infrastructure was either already present or happily footed by the local municipality where the promise of job creation and increased traffic offset the subsidies.
This was big trouble for the big airlines whose bread and butter was and always will be intercontinental or domestic travel. There was only one way they could compete against not only each other but the new LCCs.
Yup, they had to take their nice big, fast jets and cram everyone in like sardines in order to recover on the economy of scale!
The ruling economic principal of the day is now Cost per Actual Seat Mile (CASM). To boil it down to its most basic premise: the more people you can carry while using the least amount of fuel, the better. This spurred the development of ultra-efficient airliners like the Airbus A330, Boeing 777 and Boeing 787, but it also meant that airlines were now sacrificing seat pitch in order to cram more seats in. The Airbus A380 mega-liner was touted as having enough room to carry such things as duty-free shops - but really, do you think an airline is more likely to carry around something as heavy as a mini-shopping mall, and hope people will literally buy into it, or do you think they're rather just cram more seats in? The ultimate logical conclusion is now running into knuckleheads like Micheal O'Leary who runs Irish LCC RyanAir and his love affair with wanting passengers to friggin' stand during the flight.
And of course this means a lot of other amenities that were associated with the "Golden Age" of air travel - like fully cooked meals from extremely heavy onboard galleys or lounges that uselessly take up space - have gone away as well. Depending on who you ask it's even made passenger sicker, literally. First-gen jetliners took their air from outside sources much like the settings on your car; modern airliners effectively continuously recycle cabin air in order to reduce fuel consumption and aerodynamically "clean up" the airframe with as few holes and protrusions into it as possible. This means airborne diseases from someone who sneezed all the way in the back now spreads throughout the entire aircraft.
That said, I'd argue that today is the golden age of air travel. If you're willing to pay for it, you can get fancy seats in first class that recline and are in effect mini-apartments in cubicle form:
Moreover, the safety and technology available to the common passenger is unprecedented. In-flight personalized entertainment on your own computer screen; Wi-Fi internet access; and most importantly, a practical 100% guaranteed chance of arriving at your destination unharmed, in relative comfort.
Just as long as you don't mind the smell from the people next to you.