[wvenable]

The weight of the payload.

[dredmorbius]

A few ounces of shaped charge at altitude would likely lead to explosive decompression.

At lower altitude, less impact, though it would still be problematic.

Keeping the charge on the target aircraft whilst it climbed to cruising height is likely the hard part.

[jsjohnst]

Many consumer grade drones can’t fly high enough to get to an altitude where “explosive decompression” would be an issue. 5k ft is pretty doable, 10k ft is unlikely, 15k+ altitude is basically not tangible currently.

[dredmorbius]

If the drone mates with the aircraft on ground (say, during taxiing), then all it has to do is hang on to some prespecified pressurisation point.