I know sort of how you feel Bo, and as B777 said, you need to set some priorities and let the people around you know of those priorities.
If you want to be an airline pilot, piano will not help you unfortunately. Quitting the lessons is probably the answer, but I'm not going to tell you what to do. But one thing is for sure, if you aren't going to be a concert pianist, you should not be practicing 3 hours a day!! I'm lucky if I can get an hour and a half a day of practicing on the clarinet and piano together. I'm sure you could cut back a little bit.
School should be a priority for you. I suggest that one day next week, you come home and forget about everything else and just sit down and do your homework. Every last bit of it. Because if you want to go to University, that's what you need to do. Schoolwork should be your top priority You have to screw everything else, no matter what anybody says. It's your life, don't let your parents make you take piano lessons if it's interfering with your top priority, school.
As for flying lessons, I think it's crazy how high-school kids try to build flight hours at such a young age. If you are actually going to be a pilot, just wait until you're at least in college or through with college to start in with that. And believe me, if you cut back on the flying lessons, you probably won't have to work! Yes, I also think it's silly that high-school kids think they have to work, for reasons aforementioned.
Now, a personal anecdote.
While I'm only a 10th grade student, I feel much of the same pressure you're feeling. Sure, I could just breeze through my high school years by taking the easy way out, but I can't, because I have a goal. I am hoping to be accepted into the United States Air Force Academy, and it's quite a feat to accomplish. In order to make myself a good candidate for the Academy, I have to get good grades, take difficult classes, excel in sports, and be an active leader at school and in the community. Oh my god.
So, this is how I'm choosing to do all that.
In every year of high school, I will be taking the hardest classes that I can possibly take for my grade level. This year, I'm taking Algebra II, Trig, Theoretical Chemistry, Biology, English III, French II, 20th century w.hist/geo. It's tough. I get tons of homework, tons of difficult homework that I often struggle with. Now, don't think I'm just making this up. I go to what is accepted as the public high school with the academic standards in the entire state of Colorado, and one of the best high schools in the nation. It's so tough that every year kids are dropping out in order to go to an "easier" high school. I personally know one of those people. So basically, I go to a hard school.
In addition to academics, I'm involved in sports. Cross country for two months at the beginning of the school year, and track for the last two month of the school year. That means practice every day after school until 5:00, and usually once a week we have a meet which will last until about 6:00, I get home at 7:00. Sometimes that's twice a week. It leaves pretty much no time for even homework, but I force myself to do my homework, even if I stay up until midnight.
In addition to that, I'm second chair clarinetist in my school's wind ensemble. This wind ensemble is the best in the state of Colorado and was ranked among the top 1% of all high school bands, and we have won numerous national awards. This year, we are once again traveling to Indianapolis to attend the National Concert Band Festival, which our wind ensemble has attended nearly 10 times before. Obviously, the demands are heavy, and the standard is high. I need to practice about an hour per night just to keep up. Oh yeah, I play in the pep band too.
In addition to that, I play piano because I love it and it's fun. I take a lesson once a week, and try to practice an hour each night.
In addition to that, I'm involved in my church quite a bit. That takes up a lot of time, and I have to get 25 hours of community service in the coming months.
I also like photography, and I devote time to that whenever I can.
Damn! I wish I could cook me up some time, but I just can't. So I have to prioritize, and lower the expectations. During the sports seasons, the sport comes first, but I place equal emphasis on getting my homework done, including practicing my clarinet. If I can get all of that stuff done in one night, I'm happy. And yes, I can get all that stuff done easily. During the sports seasons, I have to quit the piano lessons, and I'm lucky if I can practice 15 minutes a day. I hardly ever even touch my camera either, because I have no time.
During the non-sports seasons, I can usually get everything I mentioned above finished. I still work out for about an hour each day to keep in shape.
But I left something out. Where's my social life? Frankly, I don't have one outside of school. I socialize at school, and at sports practice, and at church, but other than that, I have no social life. But I don't really care. My goal to attend the USAFA does not require me to be a socialite, nor does it require me to have a girlfriend - although it would be nice!
Here's how I look at it: I have a couple years of hell to endure. It's like running a 5K race - it's hell, but it lasts for less than 20 minutes. I can do it! And in 10 years from now when I'm flying a C5-Galaxy to Afghanistan or a 777 to Tokyo, I'm going to look back and say DAMN! look at my life now! Wasn't it worth it to just stick it out?
Good luck, you'll figure it out.