Bradley International is New England's second-busiest airport after Boston's Logan International.
The state official who gave the death toll was not authorized to discuss the investigation and spoke on condition of anonymity.
Airport officials said the plane was associated with the Collings Foundation, an educational group that brought its "Wings of Freedom" vintage aircraft display to Bradley International Airport this week.
The Nine-O-Nine, a Collings Foundation B-17 Flying Fortress, flies over Thomasville, Ala., in 2002. The FAA said the plane's airspeed was excessive and cited pilot errors.
In its 26th year, the tour has visited more than 3,000 USA airports, the foundation states.
The B-17 was built in 1945, too late for combat in World War II, according to the foundation.
Officials confirm that 14 people were injured in the crash - 13 people who were on the plane and one person on the ground - including five confirmed fatalities.
The B-17 bomber crashed shortly after takeoff Wednesday morning from Bradley International Airport. "We'd like to return, and blow it out", another pilot in the aircraft said. It also hit a maintenance facility.
Chris Ehrmann is a corps member for Report for America, a nonprofit organization that supports local news coverage, in a partnership with The Associated Press for CT. It had taken off and was in the air for five minutes, reaching an altitude of about 800 feet, before crashing.
A spokesman for CT U.S. Sen. The National Transportation Safety Board will investigate for cause and origin.
The hospital has opened its incident command center, as is typical in an emergency. "It's a loss to lose a B-17", said Hamer, whose father served in the Air Force. At least three people have been airlifted to area hospitals. The airport re-opened with just one operational runway at about 1:30 p.m. Airport officials said they expect continued cancelation of flights throughout the day.
Smoke from the plane crash at Bradley Airport in Conn., Oct 2, 2019.
The airport has since closed as crews respond. Flames and thick black smoke could be seen rising from the wreckage. It was not immediately clear whether those killed were on the plane or on the ground.
The airport tweeted from its official account that the incident involved a Collings Foundation World War II aircraft and that an active fire and rescue operation is underway.