IF, big IF, these indeed could be alien craft, last thing we really want to be doing is shooting them down. And even if they aren't, still leave them up there long enough to try to determine what and how they are doing whatever it is they are doing. Most likely they are scouts or advance recon lacking armament and minimal defensive capability.
For the sake of discussion, let's say they are alien. Shooting them down immediately identifies us as belligerents at the least and aggressors at the most. Not a good way to begin an inter-galactic relationship. That's the way it works globally, and extending it into the space environment, galactical as well.
Easy enough to divert flights around these objects drifting at airliner level. Give 'em a wide berth and see what they're up to. Allow them to drift out of U.S. airspace and onto Europe. Perhaps ESU has capabilities that can enhance overall understanding. Involve (gasp) the UN instead of the U.S. taking unilateral action that may put the planet at risk. Bit over the top on my part perhaps, but still worth consideration.
SETI's been beaming signals into space for decades. We may finally be getting an answer. Back '50s and '60s the bulk of our transmissions were buried subsurface with a minimal galactic footprint. Modern day trend is above ground surface transmission. The earth must put out a tremendous electronic communications footprint compared to 70 years ago? Perhaps enough to attract the attention of aliens??