There aren't five airports in London. There are quite a few airports with "London" in the name, but they aren't particularly close to London. London Luton Airport, for instance, is ~45km north of London, and London Gatwick is ~50km south of London. There's ~100km distance between Luton and the airport that was affected by the drones.
How do you think those planes get to those airports? There are planes flying all over the south east going to if from numerous airports. Then there’s the impact on GPS in cars, trucks, phones, police vehicles, ambulances, all sorts of emergency services. We’d have to be extremely careful about potential impact before considering such a drastic step that has a very small chance of actually being effective.
I think you might have misread my comment. What I said was that there aren't five airports in London. You seem to have understood that to mean something very different.
