a vertically adjustable armrest that is suitable for use in connection with various types of passenger vehicles , including commercial aircraft . the armrest includes a slide mechanism for permitting easy height adjustment of the armrest and also includes a locking mechanism for securely locking the headrest in the desired elevated position . the armrest moves in a smooth vertical motion and is continuously biased toward an upraised position . vertical adjustment of the armrest is accomplished by pushing a push button located in the upper portion of the armrest .