Aviation expert on the threats: "Easy to create chaos"

It is described as a wave of bomb threats that hit airlines around Europe. On Tuesday, several planes, including an SAS flight, were forced to land and be searched. No explosive substances were found and air traffic could resume - before it was time again on Thursday.

In total, it is about 20 aircraft that have been diverted in European airspace due to bomb threats. Many have had to be escorted by fighter jets, but so far no suspicious object has been found.

There are still big questions about whether the threats are connected and who might be behind them. It is clear that it creates chaos, says aviation expert Jan Ohlsson.

- It causes enormous disturbances. It takes a lot of resources from the military and other security personnel to investigate the plan. The planes are out of service for a number of hours, some airports have been closed completely for a while and then thousands of people are affected and will ask for compensation, he says.

Most of the threats have been received via e-mail. The threat email against two flights bound for Italy had the subject line "threat message", Aeroporti di Roma, which manages the capital's two airports, confirmed to the BBC.

Considering how easy it is to create such a mess, it's almost strange that it hasn't been done before, notes Jan Ohlsson.

- You can sit in peace and quiet at home and carry out these threats, he says.

- After all, security is built on every threat being investigated and then you have to land as quickly as possible, because if it's a bomb, it's usually timed.

The EU's Transport Commissioner Apostolos Tzitzikostas says that they are following developments closely and are urging countries to cooperate closely.

"It is too early to draw conclusions about whether the reported incidents are connected," he writes on X.

According to Jan Ohlsson, there is no clear common denominator that could point in any direction, other than that it is not a global problem.

- No long-haul aircraft are affected. It is only within Europe and European airlines that have received threats, he says.