I believe everyone here have already watched M Bay's Transformers movies. (but not sure if anyone here has also watched TF: Primes?) And witnessed that Megatron shown in those continuities has no earth mode! it seems to me that in those shows, he doesn't reconfigure himself as man-made machines/vehicles. Same thing has happened before as i've viewed a few episodes of TF: RID/ Car Robots, you'll see that Gigatron (To make things clearer, I refer RID Megatron as Gigatron as he was named in Japan) has no earth modes (ok! he came from Beast era factions and not Gee Ones), nor having GUN/Cannon/ Tank modes, however he has six modes (and later ten, as Devil Gigatron). one of them is alien jet. similar to Bay's Megsy who NEVER reconfigures himself as earth vehicles (or he didn't have a chance to do so since he was frozen long ago and S7 got him as a lab thing i believe) but in 2007, he transforms into an alien jet. And the same goes to his anoter self in TF: Prime, Did the designers modeled the two megatrons after RiD/Car Robots Gigatron?