Did commercial airliners have microwave ovens in the past? So I went on 2 long (total of 16 hours) flights with a major US airline, and they did not provide a free in-flight lunch (grr) during either flight. I had brought a sandwich with me just in case, but when I asked the flight attendant if they could heat it up they said that they did not have microwaves. This was I think a 757 or similar aircraft.

When I landed I was asked about my trip, the microwave thing came up and was told (by an older person) that airlines did have microwaves and that mothers with children would often ask the flight attendants to warm up bottles of milk for them...?!

So now I'm curious, did aircraft used to have microwaves in the past? Were they removed? I now know the food they serve on airplanes is "heated via hot air ovens" but why would there not be a microwave on board? Even if just for crew use?
Generally speaking, airliners do not have microwave ovens for safety reasons. I could not find any reference where commercial airplanes used to have microwaves. Probably some smaller business jets have them.

Some flight attendants mention that they can warm your food, but some say that they will not for legal and health reason.

As also mentioned by sweber in comments to the question, meals are not heated at the airport. Airline catering companies like LSG Sky Chefs prepare the meal near the airport and deliver it to the airplane. Inside the airplane, they use convection ovens to heat it.