Airlines are cancelling flights in record numbers, and delaying those that can't be cancelled. The reasons given are almost entirely laid at the feet of ATC, Air Traffic Control. That's not entirely a lie, but it certainly isn't "the truth, the whole truth, and nothing but the truth" either.
Yes, ATC is having trouble with the typical raft of regularly scheduled flights — because there are very many regularly scheduled flights... and there is a shortage of Air Traffic Controllers, and when there isn't a controller available... cancellations and delays. The other side of that coin is that we have a severe shortage of pilots to fly those regularly scheduled flights, and when there isn't a pilot available... cancellations and delays.
"Wait just a damn second!" I hear someone object. "Just two years ago, there were cancellations and delays, but not on this scale! What's going on?"
Good question. In the interim, we had a Covid-19 pandemic and a chaotic and poorly-thought-out response by many government agencies. (I'm granting the government 'the benefit of the doubt' here because I don't want to verge into that argument.) The result of that response was that many government employees (e.g.: Air Traffic Controllers) were told "take the vaccine (sic) or get fired". Some took the shot and kept their jobs; others moved into other occupations or retired. At the same time, government agencies leaned heavily on airlines to implement the same or similar policies. Many pilots took the shot and retained their jobs; others moved into other occupations or retired. The result, after all the dust settled, was that there were fewer trained, qualified ATCs and fewer trained, qualified pilots, but the number of regularly scheduled flights remained almost the same.
There is another aspect to the problem I haven't mentioned. A side-effect of the vaccines (sic) is cardiomyopathy, a condition that negatively affects the heart. ATC is a high-stress occupation, and a heart in good operating order is a virtual necessity. Piloting is, likewise, a high-stress occupation, and a heart in good operating order is a necessity, no 'virtual' about it. Unfortunately, many of those who took the shot are now finding themselves with cardiac problems. For a pilot, that is a career-ending condition. This further reduces the already-depleted ranks of pilots and ATCs, and the solution is easy enough to predict: the number of 'regularly scheduled flights' is going to be severely reduced.
Because much of an airline's costs are 'fixed' as opposed to 'variable', the airlines lose their 'economies of scale' when their schedule is shortened. As a result, expect prices for flights to rise — and that's exclusive of any inflationary pressure — and there's plenty of that. Then there's fuel. Jet fuel is fossil fuel — kerosene, and we've seen what's happening to pump prices for refined fluids, haven't we? Put it all together, and the flying public should expect a situation not much different than that pre-WW-II, where flying was almost exclusively for business purposes, and flying to the family vacation was reserved for the very, very wealthy.
Pfizer, however, is making out like a bandit. Moderna and J&J, too. I suppose it's an ill wind that blows nobody good.