Here is a list of exercise machines that are designed specifically for aerobics.
Predominantly lower body:
Stationary bike( with back seat or sans it)
Something like a “lateral” elliptical trainer( like Helix Lateral trainer)
Predominantly upper body:
Arm bike( for example Technogym Top Excite)
A standing arm bike (Life Fitness Upper Cycle GX ergometer)
Both upper and lower body:
Now, in principle you can also do aerobics on machines designed for strength training,
by putting low weight and doing hundreds of consecutive repetitions.