No to Airfields, but yes to Radars -- albeit very rarely. That rarity is most likely related to
(1) the generally very late AI pursuit of Adv.Flight which, being an optional Industrial tech, tends to be acquired well into the Modern Age, after all those oh-so-shiny Modern 1st-tier unit- and Wonder-techs. (Moving Radars from Adv.Flight to e.g. Electronics or Computers, might help a little with that)
(2) the general AI problem of never having enough Workers, which becomes especially pronounced in the late game due to e.g. the massive world wars, the AI's consequent tendency towards Fascism (which depletes its towns via forced resettlement, drafting and whipping), and Craters/ Pollution all over their land (which the AI never cleans up efficiently/ at all).