[brc]

>Have you seen many airline start-ups in the past half century or so?

Yes, several.

Virgin Atlantic, Virgin Australia and Virgin America were all startup airlines that have gone on to have success despite being in highly regulated businesses. Virgin Australia was started in 2000 with $4 million and two planes and now has a market cap of $1.5 billion. It entered an oligopoly market with two airlines and cracked it wide open.

Even companies with gentlemans agreements are susceptible to entry by new competitors - even if it requires large amounts of cash - there are plenty of people with large pools of cash looking for opportunities. It happens so often that I am genuinely shocked that people think it doesn't.