West Yorkshire Police’s Explosive Ordnance Disposal team was sent to the airport following the discovery on Saturday night.
Arriving and departing flights were delayed and there were reports of passengers spending an hour stuck on grounded planes while the item was dealt with.
The force said enquiries were continuing into the circumstances of the alert, although the incident is not believed to have been “malicious or terror-related”.
“At 8.09pm today (Saturday May 13) police were called to a report of a suspicious package at Leeds Bradford Airport,” a spokesman said.
“Following established procedures to protect passenger and public safety a cordon was put in place as a precaution.
“The airport was closed for a short time whilst the matter was being investigated.
“Officers from the Explosive Ordnance Disposal team attended and the item was subject to a controlled explosion.”
Passengers reported being kept on planes as the terminal was cleared, while at least one inbound flight was reportedly delayed from taking off at its departure airport.
Sean Hornby tweeted: “Sat for an hour now on the plane due to security issues at Leeds Bradford Airport. Tea and coffee now being offered. Hurray!”
Vicky Myers asked: “Does anyone know why Leeds Bradford airport has been closed? Sat on Dublin runway being told we can’t fly.”
Shortly after 12.30am on Sunday airport officials said they had re-opened the terminal and operations had re-started.
A spokesman for Leeds Bradford Airport said: “The safety and wellbeing of everybody on site is our first priority. After an evacuation and short closure on the evening of May 13, a controlled explosion on a suspicious package was carried out by the police. We are fully operational today and ask that passengers with any flight queries contact their airline directly.”