Amplitude modulation has a wide variety of applications, in fact, it was the most preferred technique in the past and due to improvement in technology has become somewhat less prevalent. However, due to its low cost of transmission compared to other forms as the demodulating circuits are simpler as no additional specialised components are required it died to play an important role in several applications.
Communication between Aircraft:
AM is used for the pilot to ground control and vice-versa than other techniques such as FM is because of its reception of multiple signals on the same channel.
AM is still used for long, medium and short-wave bands. The cost of equipment is cheaper. Because it is simple to demodulate and with reduced manufacturing.
Quadrature Amplitude Modulation:
In this technique, two carriers are mixed and they are out of phase by 90°. They are widely used in short-range wireless communication like WIFI and cellular networks
Single sideband of amplitude modulation waves is still used for High-Frequency radio links. Lower bandwidth is also used which provides efficient use of transmitted power. This is still used for many points to point High-Frequency Links.