I have an Indian passport and a valid US visa. I have two stopovers in Frankfurt and Munich while going to India with Lufthansa. I have a change of flight in both places. Do I need an airport transit visa?
You don't need an ATV as you are coming from the U.S., but you may need a regular Schengen Visa.
The latter depends on whether you are staying in the international part of Frankfurt and Munich Airports or if you have to enter Germany, e.g. for a domestic flight between Frankfurt and Munich. Your airline can answer you that for the specific flight you have booked