Loud, low flying aircraft noise heard in the Lancaster and Morecamber area was most likely connected to a multi-national military exercise taking place in Northern England and Scotland.
Many residents heard the sound of a large engine aircraft between 11.30pm and midnight on April 30.
The Ministry of Defence (MoD) current planned air exercise list shows that a large scale multi-national exercise is taking place between April 22 and May 4.
Joint Warrior is organised by the UK Ministry of Defence and is Europe’s largest military exercise and can involve up to 13,000 military personnel, from all three British armed forces, NATO and other allied countries.
Up to 50 naval vessels, 75 aircraft and numerous ground based units participate in a typical exercise.
Operations include airborne assaults, amphibious landings and training in counter-insurgency, counter-piracy and interstate war.
Live-fire exercises take place on various weapons ranges. Joint Warrior exercises take place in the spring and autumn and have a duration of two weeks.