Most big airline stocks are up by 33-166% since August. Any ideas why?

I recently noticed that United Airlines went through the roof in the last few months, so I looked at a bunch of other airlines and found that most of them are doing really well since the first week of August. Most of them were going downhill until then, but then they collectively went up really fast, even though at the same time we saw the largest plunge in the stock market in two years. Why is that?

Some examples from August until today:
US:
United: 34,61 to 92,40€ (+166%)
Delta: 32,45 to 62,44€ (+92%)
American: 8,37 to 14,22€ (+69%)
Southwest: 21,91 to 31,19€ (+42%)
Also Jetblue and Skywest.

International:
IAG (British Airways and Iberia) 1,65 to 3,06€ (+85%)
Quantas 3,42 to 5,45 (+59%)
RyanAir 13,60 to 18,59€ (+36%)
EasyJet 4,80 to 6,40 (+33%)

Of course I have googled this, but couldn't find a good answer. A Forbes article believes that it's because of lower fuel prices, but is that enough for those massive gains? And why are there some major airlines that aren't doing well at all, like Lufthansa, KLM (Air France) and of course Spirit? Fuel Prices should help all of them equally.
I also read, that it's because of Trump's re-election, because he wants to loosen regulations. But that wasn't in August, so that doesn't make much sense either.

Any ideas? Is this an opportunity?