I'm generally pretty optimistic but I feel that I should push back against the crowd a little here. Plenty of people say "I'd use it", but who will say "I'll pay for it"?
If you're not in it for the money, are you sure it's the most interesting, inspiring or needed tool/app you could be working on, given that it seems the competition may take care of this need anyway?
I've learnt the hard way that you shouldn't let sunk costs of a project sway your decision to carry on with it.
Monetizing something isn't the only reason to do it. And you're right too; just because you started something doesn't mean you have to finish it either.
That said, I don't know if any of the travel sites or airlines offer any affiliate programs, but that could be an easy way to monetize your site. Show users the best airport options on your end with pricing from your affiliate sites and bounce them to the airline/travel site with your affiliate code in tow if they click on the flight.
As for the idea, I've personally wasted some time scouring for airports on Google maps and then looking up the rates on various travel sites. Sounds like your site could have saved me some time for sure.
If you're not in it for the money, are you sure it's the most interesting, inspiring or needed tool/app you could be working on, given that it seems the competition may take care of this need anyway?
I've learnt the hard way that you shouldn't let sunk costs of a project sway your decision to carry on with it.
All the best whatever you decide.