Go to the AMA site for a complete list of Frequencies.

But to check it, look at the Frequency on the transmitter and/or receiver. The Crystal shoul;d have a tag on it.

If it is 27.xxx its usually AM, if it's 72.xxx it most likely is FM. But the specifications for the plane should give you that information as to AM or FM.

The Easy Star ucomes with a Hitec Focus SS AM 72MHz 3-channel radio system with HAS-03MB receiver and
two Tiny-S Multiplex servos (MPUM6521) - (AM 72 MHZ single conversion receiver I would imagine)

Couldn't find the other plane, but assume it to be similar in the Radio chosen.

Found it on the Tower Hobbies site.