how to hold your fleet back : let one random enemy aircraft go in and circle above ur base, build ship the ships will try to actk the aircraft and circle around in your base, build choppers to kill the enemy aircraft when u deem its enough :D
queen the ppl that sell you that stuff isnt the gmae maker team or have anything to do with the games selling. They r any random person out there.... so sue the game...
TDs are overrated. All you do is watch your tower kill monsters and complain about the lack of a 10x speed button. Every TD is pretty much the same.