You can't change the clock in a Aircraft.
It shows current arena time. If you are hosting a H2H session or offline, then you can set arena time.
.time (h) (m) (X)
Where H = hours (uses military time, ie 6 is dawn, 18 is dusk)
M = minutes
X = Mulitplier (0 is locked, clock does not move, 1 = 1 hour takes 1 hour)