My husband, who is a pilot told me this trick - Pinch your nostrils together with your thumb and forefinger and blow like you are blowing your nose, it equalises the pressure in you ear, and it works! - Amara xx
do exactly what amara says--i was going to suggest the same thing. hold your nose tight and blow through your noise (don't let any air escape, and you'll be good, forget chewing sweets etc, it dont work)