Spirit Airlines flight 969 was taxiing to the runway for its 6 a.m. ET departure when a passenger alerted a flight attendant to another passenger’s “suspicious activity” on board the flight, the airline said.
The flight attendant notified the captain, who decided to return the plane to the gate.
A Maryland Transportation Authority (MTA) Police spokesperson told ABC News that law enforcement escorted three males and one female off the plane. They were then taken into custody at the airport.
The spokesman said the "suspicious activity" involved one of the male passengers viewing a news report on his smartphone. All four of the passengers were "very cooperative," according to the MTA spokesperson, and have been released.
The spokesman said no charges will be filed and the incident has been "resolved."
According to FlightAware.com, Spirit Airlines flight 969 eventually departed the Maryland airport at 9:27 a.m. ET and landed in Chicago at 10:05 a.m. CT.