I don't know of any hay to make decals from household products but the are several different systems using computer printers out there. Information on unit markings can be found on the net. Use google or any search engine and look up the unit. Depending on what era you model will determine where to search for other information.
References for current units can be found at www.af.mil. It may take some time to find pic's of exactly what your looking for but hang in there.
Lastly, you can write the unit concerned and ask the for information, when I was on duty we tried to answer all unclassified requests for information.
Good luck