It could be a flying ANT, or perhaps a FLY.
bee
Bug.
Lots of 3 letter insects Bee, Fly, Ant, Bug I'd guess "be"
The answer is a simple flying insect that packs a genuine sting. It is a bumble bee, which has 3 b's and 3 e's.
Nit, a hair based parasite that feeds on your blood
3 base pairs (3 letters) code for 1 aminoacid and this 3 base pair sequence is called a codon.
it is called a POD
yea
Species of the genus Goliathus - goliath beetles - hold insects which are likely the heaviest in the world, and they can fly. According to Wikipedia, they "can reach weights of up to 80-100 grams (3 to 3-1/2 oz) in the larval stage, though the adults are only about half this weight."
Toe
UFO Unidentified Flying Object
It is called the trade name of AGA