This situation happened to me, but hopefully I can use the answer for future situations.
I was at the airport and was supposed to fly Wizz Air
LGW at 22:10 https://airportinfo.live/flight/w95752?d=2022-08-02 , but a few hours before, they announced that it would only take off at 00:31. A few gates away I saw a Wizz Air flight
LTN that was boarding to leave at 22:00 https://airportinfo.live/flight/w94452 .
I wanted to fly to London. I didn't book a coach or similar from
LGW, I didn't check any bags and it was a 1-way ticket, so either airport would have worked. However, I did want to sleep a bit before the new day, so arriving early would have been better for me.
At this point I was at the terminal after passing through passport control and security. Would there be any point in asking the Wizz air worker in charge of boarding if I could get on the other flight instead of mine? Is there any chance that they would agree to let me on (even for a small fee)? This is of course assuming that the flight wasn't fully booked.