It was AQAP that tried to bring down Northwest Flight 253 over Detroit on Christmas Day 2009 using a Nigerian recruit who had secreted a hard-to-detect bomb in his underwear, and it was AQAP that smuggled bombs in printer cartridges onto cargo planes bound for the U.S. in October 2010.
And he himself was directly involved in plotting terrorist attacks against the United States and American citizens, including the so-called underwear bomber who attempted to bomb an airliner in December of 2009, and the failed attempt to bomb cargo planes headed to the United States.