This is the answer, unless you fly a lot, in which case you'll have to remember to pack it or else you'll lose it to the TSA.

I would go for a relatively small knife with one strong blade, as opposed to a Swiss army type. Here is one : https://www.amazon.com/dp/B00S1WXLRI/ref=cm_sw_r_awd_OpsVvbDQDRA66