[btgeekboy]

No need. A Canada Goose[1] can take out an engine; a flock can take out an airliner.[2] There are many drones larger than the geese, so I would expect this to be a distinct possibility.

[1] http://en.wikipedia.org/wiki/Canada_goose [2] http://en.wikipedia.org/wiki/US_Airways_Flight_1549

[dzhiurgis]

> usually weighs 2.6–6.5 kg

Flock of drones is unrealistic too.