United used to paint planes while in HMV in SFO. Now I think a seperate contractor does it, but i'm not sure. I know that it is not done in California, due to laws about the paint.
Here is how it was done...well sort of!
1. The paint is stripped.
2. Bare metal is left.
3. ** The plane is inspected for any cracks or fractures that may be covered up by the paint.
4. The plane would be masked. Everything from windows, to parts of the body were covered. The masking was paper bag like material.
5. A primer coat is applied
6. The Blue bottom, is painted.
7. The gray top is painted
8. The stripes are painted including the tail
9. The tail logo is painted
10. "United Airlines" is painted
11. Registration, and the nose number is painted
12. The masking is removed.
13. You have one beautiful plane with that fresh paint.