Anne ,
FM seems to be the favored mode no doubt . In the earlier days however AM was used in quarter scale NASCAR and USAC midget type gasoline powered ,spark ignition engines . It was also used in many spark ignition powered planes in the early days of Quadra powered type giant planes. The negative comments regarding AM are sometimes overblown. Much of the reliability we now enjoy stems from better RX design and the credit is coat-tailed over to FM. AM does demand better equipment design and beginners tend to have an easier time debugging FM problems that are noise related .
I do agree that safety should take the front seat and a modern FM radio would be the best bet. Just wanted to give AM a fair rap
The comments about 27 mHZ someone else made may be in error. I can't put my fingers on the rules right now ,but as I recall 27 is allowed 2 or 3 watts power. I will try to find the section.
Cheers to you,
EllEff