The unprecedented security measures have come after claims by police in Pakistan and Britain that they foiled an alleged terror plot to blow up 12 trans-Atlantic passenger jets.
Flight cancellations and long delays has left thousands of passengers stranded at airports across the country, including commuters at Manchester and Leeds / Bradford airport.
Police have arrested 24 suspected terrorists in London, High Wycombe and Birmingham.
Two British nationals of Pakistani origin were held in Karachi and Lahore after being arrested the week previously and police say they provided important information regarding the UK plot.
Police said the explosions could have caused "mass murder on an unimaginable scale".
It was reported that the suspects were planning to blow up several planes above five major US cities by using liquid explosives carried in soft-drink bottles, and detonators disguised as electronic equipment like MP3 players and mobile phones.
Following the arrests, airports throughout the UK issued strict new security measures. Armed police have been deployed in many airports and passengers are no longer allowed to take their hand luggage into the cabin.
Home Secretary John Reid said the police were confident that the "main players" had been accounted for. But US government sources claimed that British officials were aware of five suspects who remained at large.
Reid has urged people of all communities and religions in the UK to join together to overcome "those who wish to harm us".
Reid praised the fortitude and patience of passengers affected by the increased security at airports across the UK.