An EMS Plan 1- which immediately brings five ambulances and additional manpower to the scene- was called after a crew member reported smoke in the cockpit shortly after takeoff.
Several fire trucks were standing by as the jet landed safely just around 6:40 a.m.
United Airlines spokeswoman Mary Ryan says the plane landed safely and taxied back to the gate, where all 44 passengers got off the aircraft.
No one was injured.
The EMS Plan 1 was eventually struck out, according to officials.
The cause of the reported smoke is unclear.
The Associated Press contributed to this report.