To respond to beyond,
I never said that I don't like boats; I said that I like planes. They aren't mutually exclusive.
Also, what's wrong with choosing the USMMA because I didn't get into another one? I'm not going to lie. The USMMA is last on my list, but that doesn't mean that I'm settling for it. I'd be more than happy to go to any service academy. That's like saying don't go to West Point because you didn't get into The USAFA. As the other posters have said, sometimes going to a different academy is the best choice after all.
Thanks for all of the feedback though.
The point he was making is that you are going to be spending four years studying maritime subjects, and that you better have an interest in shipping, as that will be your life for four years. You won't touch aviation until after you graduate (that tends to be the case at a lot of places, however). More than that, you'll compress your academics into three years so that you may spend a fourth at sea on commercial vessels. Accordingly, more than a passing interest is necessary in the maritime industry, or else you could find yourself being rather miserable.
The opinions of beyond and jasper are fairly common among USMMA alums, both on this forum and elsewhere. They do not like the idea of their alma mater being thought of as a catch-all service academy for those pursuing commissions in the active branches (but who were denied appointments to the respective SAs). The USMMA has a purpose separate from the other service academies. Yes, there are active duty options from USMMA, but those are not the principal reason for the school's existence.
If a student chooses USMA because he didn't get into USNA, then he is making a drastic change of plan, as now he is going into the Army instead of the Navy. If someone wants the Navy, it seems a more logical choice is to pursue NROTC in that situation. That said, if service is the goal, no matter what branch, then it makes little difference if USMA is accepted because USNA fell through. USMMA, however, is a different animal. The academic and Regimental program is unique in its goals. The default result for a graduate is to be a licensed CIVILIAN mariner who works on US-flagged ships while participating in the Naval Reserve. Active Duty is an option, as you note, but unlike USMA or USNA, that is not where the institution firmly has its place (the default result for a USMA graduate is to be a 2LT in the Army). KP gives more options than any of the others, but it is, as jasper notes, first and foremost a maritime academy.
As the others have said, you certainly can become a pilot in any of the branches from USMMA. Are you willing to spend four years studying marine transportation/marine engineering, to include spending a year on a commercial ship, in order to get there? Or, would you rather focus your efforts on branch-specific programs to further your chances at flight school, all the while studying subjects unrelated to the maritime industry? If the answer is yes to the second question, you would best be advised to pursue the service-specific SA (USNA, AFA, etc.) as a first choice with a ROTC back-up (and potential re-apply to the SA). If, however, you really do have an interest (that is more than passing) in commercial shipping, are willing to study it and keep your options open, then USMMA is a good choice (back-up or not).
All the posters above are advising is to be realistic about what you are undertaking.
I was Air Force AD and graduated from VMI, so I have no dog in the hunt. However, having participated on these forums for a while, and having volunteered at college fairs, that is how I would advise you approach the issue.
Pay attention to what the alums from KP have to say. Their input is the most valuable.