I have been told that there is no actual plane in the lake. Supposedly they put a tail fin from an old F-4 Phantom on a pole embedded into the lake bottom to scare the rookie pilots that were training at the old Grand Prarie Naval Air Station. Don't know if this is true or not though but the story of the entire plane sounds a lot more interesting...
There is indeed an aircraft in the south end of the lake.
http://aviation-safety.net/database/record.php?id=19750304-0%E2%8C%A9=fr
As far as fishing the lake, it still produces, I grew up fishing it, but the best largemouth I ever caught from it was just over 6 lbs. Nice fish, but no monster. It is, however full of aggressive and strong 3 lbers.
As a kid it was always a great white bass and crappie lake. I've seen 20+ freshwater drum in person, and saw a photo of a 40+ from that lake.
They stocked reds in it in the 70's as well, but I never saw one, or heard of anyone catching one back then. Maybe the whites ate them (hint).
Dallas has been patrolling the Grand Prairie side of the lake (although still Dallas, I guess) a lot more, and the location of the old ramp (just north of the 303 tollway) has been safe for me to park at several times over the past few years when taking a kayak out there.