As we can see from the screenshot above, airplanes avoid Iraqi and Syrian airspace due to ongoing conflict in both countries.
On the other hand, in Saudi Arabian airspace, alcohol is not allowed to be served onboard. Since there are many airlines serving alcohol in-flight, therefore it is better for them to avoid Saudi Arabian airspace altogether.
Airliners usually avoid hostile regions at all costs. This is based on advisory from international body such as ICAO and United States’ own Federal Aviation Administration (FAA)
Malaysia Airlines, from its Facebook page, has posted an announcement about its flights to/from London. Below is the announcement:
[ALERT] FLIGHT OPERATIONS TO/FROM LONDON
Due to the current severe weather conditions across the United Kingdom, Malaysia Airlines flight operations to/from London Heathrow may be retimed.
Please check status of your flight with us at http://bit.ly/MHflightstatus or call us at toll free number 1 300 88 3000 (within Malaysia) or +603 7843 3000 (from outside Malaysia) for updates.
The weather disruption is due to the severe accumulation of snow. LANDASAN would like to advise our visitors to check with your respective airlines for rescheduling and keep yourself updated with current information.