The US believes that Islamist terrorists are developing bombs that could evade existing airport security checks.
While there is not thought to be any specific threat the fear is that Jihadis with Western passports and who have been trained by al-Qaeda, could enter airports armed with bombs that are almost invisible to air travel security measures.
ITV News Diplomatic Correspondent John Ray reports on the new security steps being put in place today:
More top news
It will be a cloudy and at times damp morning across much of the UK, apart from the far west where it will be dry and bright.
Barack Obama has returned to the political spotlight, campaigning for Democratic candidates ahead of upcoming elections.
The prime minister said there was a "clear and urgent imperative" to give new impetus to stalled negotiations.