Homeland Security Secretary John Kelly made his remarks during the Memorial Day weekend - one of the busiest travel periods in the US. Kelly said that terrorists were "obsessed" with the idea of "knocking down an airplane in flight - particularly a US carrier, if it's full of mostly US folks."

"There's a real threat - numerous threats against aviation," Kelly told the Fox News less than a week after the bombing at an Ariane Grande concert in Manchester in the United Kingdom.

The UK has since raised its security to the highest level in ten years, fearing that further attacks might be planned especially at hubs of public transportation, such as train stations and airports.

Last week, Kelly already met with European Commission officials in Brussels to discuss further details about a possible laptop ban in airplane cabins. However, the air travel industry has already been highly critical of the idea. 

Expansion of existing ban

The move would dramatically expand a ban announced in March that currently affects roughly 50 flights per day from 10 cities - mainly in the Middle East and North Africa. This current ban was reportedly put in place because of concerns about terrorist attacks and related risks. Countries that are affected by the present ban are Turkey, Jordan, Egypt, Saudi Arabia, Kuwait, Qatar, the United Arab Emirates and Morocco.

Travelers from those destinations are barred from bringing laptops, tablets and a number of other devices on board with them in their carry-on bags - regardless of their nationalities. Electronic devices bigger than smartphones have to be checked in on those flights. Some of the airlines affected by the ban have tried to implement workaround solutions, especially for business class travellers, such as making complimentary laptops available to those afftected.

A ban that would encompass all international flights would likely follow a similar pattern.

ss/rc (AFP, AP)