I have been a professional electronic technician for over 40 years now, with nearly 37 years working in calibration and repair of computerized test equipment. I have experience in the entire spectrum of electronics, from TTL to high voltage analog, DC to microwave RF.
One thing I've learned in that forty plus years, is that some things are just better purchased off-the-shelf, rather than trying to build myself. You can waste a LOT of time and money trying to debug an unproven design, and when you start talking about something like a radio control unit for an aircraft, you run the risk of possible injury or property damage if its deficiency decides to manifest while your plane is in flight.
Good transmitters can be bought for under $50, and six channel receivers for $20. My Tx is a bit more expensive, but it has additional features such as multi-model memory. In all the times I've flown, it's never given me any issue, nor any reason to worry. It's also about as impervious to interference from other transmitters as any unit today can be, which is something I wouldn't want to bet a home-built would be.
Add to this the factor of trying to work in micro electronics and surface-mount components. Many of these components require an extremely fine solder tip AND a binocular microscope to properly assemble to the circuit board. One nearly impossible to see solder-bridge between two circuit pads can result in a destroyed component, or - worse - ruined circuit board. If you want your receiver lightweight and small enough to easily fit in an airplane, and that's what you're going to need to work with. I can tell you from experience, it's barely worth getting paid to deal with micro-circuitry like that, let alone doing it for "fun."