Some airlines are flying longer than usual

JAL43 from Tokyo (HND) to London Heathrow (LHR) tracked via RadarBox.com - Comparision - February 20 and March 15, 2022

Following the war in Ukraine and the airspace restrictions due to the Ukraine-Russia conflict, several airlines have been experiencing increased operating costs with detours and consequently longer flights, generating more costs.

JAL43 from Tokyo (HND) to London Heathrow (LHR) tracked via RadarBox.com - February 20, 2022

Flights such as JAL43 from Tokyo to London have added 2:50 hours to their flight time. This flight, for example, which used to operate the route from the east to west, is now using a Pacific route over the USA to London Heathrow. 

JAL43 from Tokyo (HND) to London Heathrow (LHR) tracked via RadarBox.com - March 15,2022

Most european airlines, such as British Airways, are also completely avoiding Russian and Belarusian airspace due to imposed airspace restrictions, taking long hours to land at their destinations in the UK. 

BAW10 from Bangkok (BKK) to London Heathrow (LHR) tracked via RadarBox.com - February 20, 2022

BAW10 from Bangkok (BKK) to London Heathrow (LHR) tracked via RadarBox.com - March 15, 2022

LH648 from Frankfurt (FRA) to Almaty (ALA) tracked via RadarBox.com - February 20, 2022

LH648 from Frankfurt (FRA) to Almaty (ALA) tracked via RadarBox.com - March 15, 2022

And here's the LH648 flight operated by Lufthansa from Frankfurt to Almaty that suffered due to airspace restrictions. Other airlines like Finnair, which used Russian airspace for their flights to Asia, are using alternative routes.