How effective would it be to strap a jammer onto the front of the planes and just turn it on during landings and takeoffs? Basically create an anti-drone force field around the planes.
Not a bad idea at all. Although the tech would not be difficult to develop, deploying it and maintaining the system by the aircraft companies is unlikely in the U.S.'s system (based on today's drone "risk" statistics, at least). I also believe that a localized ground-based jamming system is better, for the simple reason that it's a lower cost for the upkeep. Long term operation of a highly-radiating aircraft antenna (with high directivity) in the temperature range of Atlanta's runway vs. Anchorage's has some engineering challenges.
The thing is the only ability to jam wireless signals I am aware of emit a strong noise-type signal that makes picking up any real signals impossible. It's like screaming loudly in a room to interrupt another conversation. Imagine a plane doing this while flying over a bunch of homes, or coming in for a landing. Ultimately I think that this is a matter of a new tech that just needs to be regulated and clamped down on, as it's free use is causing problems that are larger than the benefits of the freedom of buying and using drones without regulation, so drones will need to be.