I don't understand why, but when I try using air, and when I try playing a little loud(fortissimo) I drop notes. This seems very contradictory to people when they say, "Use more air to play high notes." When I try to use air, it never works. For example, a B flat above the staff (Not the C, a trumpets B Flat) I can play it better, quieter. But, when I go to a fortissimo, I drop it every time. Why is that? Any advice would be great.

Your embouchure is not fully developed for that range. Advise, keep practicing. Using more air is only 1 of many parts that need to work together to play loud and high. Only smart practice and instruction in this area will be of benefit.

I agree with getting lessons. That's the long term solution. In the meantime, I look at it this way. Some notes we own and some notes we rent or borrow. You don't own the Bb quite yet. Probably due to the facial muscles' strength. If Bb drops out, go down a third to the G and make it yours. When you own the G, take it up a whole step and start taking ownership of the A over a period of days or weeks. The Bb is only a half step away !! Take small methodical steps after a warm up period. Don't spend 10 minutes trying to own the G. You'll wear out and frustrate yourself. If it isn't there, go to the F and start there. Good luck.

For example, a B flat above the staff (Not the C, a trumpets B Flat) I can play it better, quieter. But, when I go to a fortissimo, I drop it every time.

In a nutshell, kinda sounds like weak chops. You're note quite where you can play that note ff.

To me it sounds more like bad breathing habits.

When we tell our body "DAMMIT; BLOW HARDER", all we succeed indoing is raising the tension everywhere. The secret is to get the volume with MINIMAL increase in tension.

I will question the probability of getting that right with internet advice. A good trumpet teacher could sort that out in a live lesson very quickly. They see what your body is fighting.

I agree with Rowuk. To truly address your problem, one needs to watch where your air is coming from when you change dynamics from mf to f. The air support needs to come from down low in your airway, and not forcing from the upper airway (above the level of the glottis - in the neck region). To try to force air above the glottis only causes increased resistance (through tension). It IS a fight and you need a referee (teacher) to judge the match. The best fighter in this situation is the looser.