I don't think either can be saved. Badly exposed, poor detail. Just plain nasty. (sorry - you did ask)
There's plenty of good advice on this thread from plenty of different people.
Pics always look better with the sun shining full on the aircraft. And the public areas often give poor results compared to other places you might find. You need to go to a little trouble to either be at the public area at a time when the sun is mostly behind you (and therefore shining on the right side of the aircraft), or else find a spot somewhere else where the sun will be behind you - most airports offer SOMEWHERE to shoot from, and in the US you have an advantage that in most airports you can get through the security check to the gate area, where there is usually glass to shoot through, even if you are not travelling.
At the moment, everything is against you: for a start, using a flatbed scanner, you need the very best quality originals in order to get them accepted. You need to have good quality prints that are SHARP before you start. If you look at a full-frame 737 shot, for example, then if the fuselage detail isn't SHARP on the print, you probably won't get enough detail in the scan. (Can you read the reg. number, for example?)
As a first step in improving things, you must WANT to take better pics (do you want better quality pics, or just a site that will accept the quality you have now?). Second step: get to the airport on a SUNNY day, at a time when the sun will be behind you so the aircraft will be well lit. Or else explore, and see if you can find somewhere else at the airport that will give you the view you want, with the sun in the right place. Then try photographing aircraft taxying (slow movement - less to go wrong). See if you can get them either completely side-on, or mostly side-on, and try to mostly fill the frame.
Your camera is manual focus, so pay special attention to getting the focus right. If an aircraft is taxying slowly, you probably have a few seconds in which you can fine-tune the focus to get it as sharp as possible. Make sure that your shutter speed is a MINIMUM of 1/focal length of your lens: in other words, if you have your zoom set at 200mm, your shutter speed should be at LEAST 1/200, higher if possible. Hopefully, you will be using fairly slow print film - ISO 100 is best; if you can't get that then ISO 200, and use Kodak or Fuji if you can, not cheapo Polaroid, or K-Mart own brand film. This should give you better colours and less grain.
You need to put all these things together in order to get a good pic. When you get your photos processed, you might consider getting prints done to 7x5" rather than 6x4", as your scanner should be able to pull more detail from these. When you get your pics back, you need to look at the results with a critical eye. If they are not well-exposed (too light or too dark), don't scan them. If they are not crisp and sharp, don't scan them. Basically, if the original is not of high quality, you can't put that back when scanning and editing your shot.
I hope this whole thread helps you. There are some people who will say "we are fed up of people like you moaning, get lost and go someplace else". However, there are also plenty of people like myself, Ckw, EDIpic, Granite, Cyka, and many others who would rather take the time to write these sort of responses to encourage you. You don't need to give up, not if you want to take better shots. Most people can do it with practice, some patience, and a few helpful tips. I would also offer the following: nobody started out as a good photographer - we all had to learn. And you learn by taking pictures for yourself, and taking advice from people who have already been there. We've all been there, we've all taken TERRIBLE pictures, and we all decided we wanted to do better, and we learned from our mistakes.