I have been doing a good bit of research lately into a new form of electric "jet engine" developed by researchers in Wuhan, China; in the article summarizing the technologies used to produce this remarkable device, they state that they used a compressor in conjunction with a cavity magnetron to produce a high-temperature plasma, that was then ignited by a spark plug and accelerated up a quartz tube to produce thrust.
During the two college chemistry classes I took, however, I learned that microwaves are not necessarily the most high-energy form of radiation on the spectrum, and are thus considered to be non-ionizing. My question is whether or not it is indeed possible to achieve air ionization solely by using microwave radiation.