ROBERT JOHNSON, TRANSPORTATION SECURITY ADMINISTRATION: The TSA screener workforce is thoroughly vetted, completely turned upside-down and inside out, when it comes to knowing what their backgrounds are. And when we find problems in that process, we deal with them immediately.
FRANCIS: Well, not quite. Even the TSA admits that more than one- third of all screeners -- that's more than 17,000 -- have yet to complete their final background checks.
New York Senator Charles Schumer is one of TSA's critics.
SEN. CHARLES SCHUMER (D), NEW YORK: The fact that the most rudimentary thing, like a background check, isn't being done, and that people with criminal convictions are getting the job, make you scratching your head in wonder. What the heck was TSA thinking?
FRANCIS (on camera): Being generous, say experts, the standing-up of such a large security force so fast has gone remarkably well. The question is, whether TSA can get over what they call growing pains before the next terrorist attack.
Fred Francis, NBC News, Washington.