ST. LOUIS COUNTY – The next time you fly you might not have to wait in those long security lines.

The Transportation Security Administration has expanded its pre-check service at Lambert-St. Louis International Airport, and it could save you a lot of time.

The decisions are completely random, but if you receive a pre-check logo printed on your boarding pass, you get to whiz through security with fewer hassles than in the regular security line.

Most people though don't realize they've been approved for pre-check.

The TSA screens all passengers in advance. If you're not on any watch lists, you're eligible to go through the pre-check line.

The advantages? For one, you don't have to take off your shoes or jacket. You can also leave most electronics and liquids in your bag.

Right now, more than 30 percent of Lambert passengers are qualifying for pre-check and they're liking it.

"Pre check is the best thing ever. It's very convenient; you don't have to take anything out of the bag. You can fly right through and usually it saves a lot of time," said traveler Tom Klima.

You may be wondering if this pre-check program changes the level of security at airports? The TSA says safety in the skies hasn't changed.