I need to work on my upper register, some days i can hit high C and others i cant even hit a G(above staff) it just is all air. I dont understand the problem, any help would be great.

I have exactly the same problem and desperately need help, since I am playing a piece that requires me to hit a B above the staff. It`s urgent!

ok frist do u but air behind the horn yall on this site think range is all about the way ur lips are on the mpc well tha is a part but not all U NEED LOTS OF ARE AIR for me its lots of air whin i go above a E (above the staff) for yall i would start blowin ur brains out when u get to a F (not tryin to brag just telin yall it is different for different people)ok if ur doin that make sure u dont press the horn ro ur lips that kills the viberation (i do it to and u just gatta think Dont do that it will mess u up bad) ok make sure ur lips are tight but not so much the side of ur lips but the part in the mpc ok if this might wanna try some breatin exersises just fill ur body up withj air and blow it all out...hope it helps
what ever u do dont get mad that tighten ur muscles including ur lips killin the viberation (same with gettin nerves..hint hint)

actually faster air equals a higher pitch. more air equals a louder sound. your problem is you are trying to play notes that you aern`t ready to play. you need to work your way up to them. do lip slurs and long tones for at least 10 minutes a day. the more you do the better. do the lip slurs slow for maximum results. after you`ve done the lip slurs play arpeggios 2 octaves starting with the lowest one and working your way up. don`t push the trumpet into your face. let your tounge do the work. don`t buy a mouthpiece to help you play higher notes. that will kill you and screw with your tone. i play a bach 1.5 c for jazz and a bach 1 b for concert and i can play up to a double c on both and a triple g on the 1.5c. working mouth strength is better than buying your range. hope i helped