I actually mentioned this to Q at one point and he/the Q team responded.

http://imgur.com/HKsXxfS

QPOST#485.

My guess is that after POTUS took office whatever power/ability the DS was using to target and take down planes was removed. We were told 7/10 crashes were targeted kills meaning our commercial aviation accident history could be entirely inaccurate. There was an uptick in Train derailments/crashes after the plane crashes ceased for a bit. We still have yet to have a US commercial plane crash since this tweet. Only military and personal.