Howard, I used iron on covering film, silver colour, from HobbyKing. I was trying to source the ultralite version but with everything at a halt no supply anywhere.
The decals were a mix. The large aircraft numbers are solarfilm as are the roundels, tail markings and jet warning in yellow - all ironed on after peeling the designs from a cutting backing sheet using masking tape (just iron the masking tape and then gently peel off as the films hot glue melts and sticks to the models surface). The small aircraft numbers near the fin, I did in black adhesive vinyl. Too small to risk stuffing up by ironing it on. All cut using a vinyl cutter I have here.