Many complaints about TSA come in the form of posts on social media websites like Facebook and Twitter, but the agency's numbers only reflect formal written complaints.
TSA also said in its midyear report that its Pre-Check known traveler program had been expanded to five airlines and 20 airports. The program, which is part of the agency's move to "risk-based" security techniques, allows passengers to volunteer information in exchange for the possibility of receiving expedited screening.
The agency said it found 821 guns in passengers' carry-on luggage so far in 2012, of which 210 were loaded with ammunition.
"Firearms have been found at a total of 160 airports with Atlanta (ATL) TSO’s finding the most firearms – 56 found so far this year," Burns wrote.
TSA said it has also discovered a grenade, a bottle filed with flash powder and fireworks in passengers' luggage this year.