Realistic yes, it's expensive and not that convenient. There are people who live out of RVs or boats, traveling around for years with no fixed abode and it works out fine because there's an infrastructure they can use. An RV can stop at a grocery store to stock up on supplies, get deliveries or food or shipping at campgrounds and RV parks. Boats can dock at large marinas, many of which have supermarkets attached. In both types of places you can hook up to electricity. Many permanent RVers pull a small car on a trailer, so they can range out from their campground, explore, resupply, take care of business, etc.
A large enough airplane could be converted into a flying RV, although I'm not sure how you'd set up cooking arrangements if it's a pressurized fuselage. There are some considerations and challenges to making it work:
- Most airfields are far away from towns and cities which have amenities, or sites you'd want to visit. You'd need to be choosy about where you go
- Airfields are not set up to provide convenient hookups to RV-style airplanes, you'd need a lot of batteries and limit yourself to low power applications. This is totally workable, just not as convenient as having a hookup. You could get a truck to give you power, which is expensive - you wouldn't want to have it 24 hours a day, presuming one was available
- Transportation out of the airfield could be a problem in some places. Some FBOs have a courtesy car to borrow, some do not. Some areas have taxi services and some don't. You could probably pack a moped away somewhere to get around that, of course there's limits to how much you can carry on one of those
- Airfields don't have convenient markets for re-supply, you'd need to leave the airport for everything
- If the airport is commercial you may have to pass through security every time you want to get back to your airplane
- If an airport has a closing time you may not be able to get to your airplane after hours
- Some airfields will let you camp by your plane, some will not
- Airplanes aren't designed for comfort when still, there aren't lots of windows you can open up to get fresh air. You'd likely need some sort of AC system, which requires power
- You'll need to pay ramp fees, which are parking fees for your airplane. These vary a great deal from airport to airport, a small jet at a small rural field may be $10-$20 per night (cheaper than many RV parks!) and waived for a week if you buy fuel, the same plane at Teterboro, NJ would be $300 per night
- It would cost serious money to re-do an airplane as an RV because the materials must be lightweight, and to get it certified will be expensive as it's a one-off build
- Airplanes are very expensive to own and operate to begin with
None of these are deal breakers, it's just a matter of money.