[teovall]

Aviation still uses AM radio which is more susceptible to noise than FM or digital modes but it does so for two very important reasons.

The first is that, with AM, if two or more people are transmitting on the same frequency at the same time, they can all still be heard. With FM, the strongest signal will suppress any weaker signals and only one signal will be heard.

The second is that even very weak AM signals have the chance to be received and understood. The human ear is very good at picking out human voices from noise. Weak FM signals just drop out completely.