The VX7 does key up in the aviation band, however I'm not sure how much power it outputs there nor if it does so in AM. The further you get from the ham bands the less efficiently the radio operates and the less power it will put out, especially with the factory rubber duck antenna.
Actually the power it puts out is the same, it's just that the antenna is less efficient. However, you can easily make a new antenna for whatever band you plan on working. A simple quarter-, half-, or full-wave antenna can be made out of a piece of electrical wire (the kind used to wire houses) and a small (4" square) piece of copper sheet for a ground-plane. 
I do not disagree that ham antennas perform poorly outside of the amateur bands, but the radio itself is a factor as well. If someone has access to this radio, a Bird wattmeter and a dummy load and can prove that this radio can transmit a full 5 watts from 40-225 and 300-580, I'd be very amazed. I know that the PLL starts to become unlocked at around 550 so I can say with some certainty that a full 5 watts is not being output there, even into a dummy load, or a telescoping antenna adjusted to a quarter wavelength although I wouldn't do anything illegal like that
However, there is hope that this radio does in fact put out a meaningful amount of power on the aviation band, as it is quite close to 2m and even closer to the bottom end of the CAP band. Also, Yaesu a.k.a. Vertex Standard makes a radio which looks identical to the VX-7 for the aviation band, and it's a dual band aviation and 2m radio in one which is quite unique for a radio commercially sold and type approved for VHF aviation. The model is the VXA-710 (even similar in nomenclature) if anyone cares to look it up. It is more expensive than the VX-7R and lacks many of the features which the 7R posesses. however one must wonder with its nearly identical looks how different the guts of it really is. Is there just different software burnt into it? Who knows. It is this striking similarity which leads me to believe that the VX-7 could function well enough to be useful on the aviation band if an occaision arose where I had to use it there.
As a private pilot...
Wow. I've always wanted to learn to fly. Do you own a plane?
No, I rent Cessna 182's fixed gear. Those little planes, most a few decades old, are more expensive than people think. $100k or better unless it's 50 years old and a fixer upper. A new one will run you about $300k. Renting isn't exactly cheap either but if you only fly once in a while and you're not independently wealthy, it's the way to go. Our club's rental fees just charge by engine running time and includes the price of gas (100 octane low lead) provided you get it at the club's airport. If you fill up elsewhere, they'll reimburse you the price at the club's airfield and any difference in price you'd have to cover yourself. Having it go by engine run time is nice so you can take a vacation somewhere and park it for a week without worrying about being charged for the time it's just sitting there, besides the parking fees at whatever field you land at of course. On the other hand, if you want to take a trip during a popular vacation time of the year, you have to reserve the plane pretty far in advance before someone else takes it for at least one of the days you had planned on having it for.
True. I guess I should really watch what kinds of things I say around here, lest I come off as advocating the wrong activities.
It's mostly a CYA thing, but I draw the line at putting human lives into jeopardy. I just think that a lot of these people who screw with ATC frequencies don't realize what could happen not just to them legally but to those in the air who rely on these frequencies to arrive safely to their destination. Everything isn't automated yet. There's still a lot of human involvement, especially if conditions are IFR. When you're up there in IMC and you can't see a damned thing, that radio and the ATC controller on the other end of it is your lifeline to make sure you're not going to crash into anyone else in that cloud. Those little radios on the ground might only go a couple of miles without a different antenna higher up, but for someone in the air it is not uncommon to pick up signals hundreds of miles away. The potential is there to interfere with one heck of a lot of air traffic. Let me also take this opportunity to let people know that transmitters can be found quite easily by direction finding or DF for short. Hams do it often with transmitter, or "fox" hunts and you can bet the FCC and others have some pretty sophisticated gear to accomplish this. Doppler DF systems can gain an azimuthal lock on transmissions of less than one second, and this can be done with equipment any ham could build in his basement for less than $100.
So, in closing, have fun, but think first, don't do anything that could potentially cause another human being to be harmed and/or killed, and don't ever believe it's impossible to get caught.
