That's a fairly brazen ripoff, though changing the plane to a Sopwith Camel is enough to escape any legal troubles. It's just a pity this is what developers resort to when they lack ideas.
There's a pretty big difference between being inspired by games in the past (see below), and systematically copying one specific game piece by piece - name included.
I'd like to note that I actually hadn't played any game like Stunt Pilot when I wrote it, although I've since played Pilot Wings. Stunt Pilot was designed to be a playable version of air racing.
http://www.rocksolidarcade.com/games/stuntpilot/ http://www.squiddlegames.com/stuntpilot/