"Most flights are booked 80 to 100 percent, so it will be crowded in our terminals and on the roads accessing the airport. So we encourage all passengers to be vigilant," said airport police Asst. Chief Ethel McGuire.
City, county and federal law enforcement agencies are launching a public awareness campaign to remind travelers to report suspicious behavior.
Some examples of suspicious behavior include: someone leaving behind a bag or briefcase, measuring or drawing important buildings, asking about building security procedures or leaving a car parked in a no-parking zone next to a building.
"Trust your gut. If something doesn't look right, if something doesn't seem right, then something is probably wrong," said Randy Parsons of the Transportation Security Administration.
"We might get a number of reports that amount to nothing, but among those many reports, may be the prevention of a disaster," said Los Angeles Mayor Antonio Villaraigosa.
Some commuters said that the campaign makes sense, especially as the holidays approach.
"I think that's great. I think more awareness is better. I should probably be more aware myself," said one commuter.
"The conductor told us to pay attention to things around us and if we see something suspicious to let him know. So it did make me more aware of what was around me," said Debra Gardner.
Anyone who sees something that raises a red flag should tell a police officer or call (877) A-THREAT.