Baltimore/Washington International Thurgood Marshall Airport now has free WiFi for its travelers, after previously only offering a paid service at the airport.

But the free perk announced Wednesday has its limits. Travelers will get 45-minute sessions at a time. Under the new system, travelers also will need to watch an advertisement at the start of each session.

Those who want more bandwidth and no commercials can opt to pay for the premium service.

"This new, free WiFi service will provide an improved level of convenience for our travelers," BWI Executive Director Paul J. Wiedefeld said. "BWI Marshall emphasizes customer service and efficiency for our passengers. The improved wireless amenity will allow travelers to stay connected."

The airport is slow to the WiFi game compared with its closest competitors. Ronald Reagan Washington National and Washington Dulles International airports added free WiFi in April 2011.