ILNA - Managing Director of Iran Airports and Air Navigation Company Siavash Amir Makri said Iran�s revenue from overflight fees was about $300-350 billion a year.

Speaking to ILNA news agency on Wednesday, the Iranian official said that many flights have been avoiding Iranian airspace by taking a more northerly route over Afghanistan and Pakistan or a more southerly route over Saudi Arabia.

The average earnings per flight from the Iranian airspace is not less than $800, and about 950-1,000 flights pass through the Iranian airspace on a daily basis.

�Overflight fees in Iraq and Afghanistan are fixed, $375 and $400 respectively, but overflight fees in Iran are about $100 so using the Iranian airspace is cheaper for other countries.

For commercial airlines and freight carriers, flight restrictions mean taking the long way around, costing time and money.

The additional miles flown to avoid trouble spots mean higher costs for airlines, which together spend $180 billion a year on jet fuel.

A Ukraine International Airlines Boeing 737-800 plane with 167 passengers (including Iranian and foreign citizens) and 9 crew members on board was crashed Jan. 8, after taking off from Imam Khomeini International Airport in Tehran. Following the investigation, the General Staff of the Armed Forces of Iran released a statement saying that the Ukrainian aircraft was unintentionally shot down by Iran, due to a human error.

�We cannot cancel or delay flights due to security conditions in the country unless ordered to do so by a higher level authority,� Makri told in another interview.

Approximately 1,000 commercial planes fly through Iranian and Iraqi airspace each day, Albert Tjeong, assistant director of corporate communications for the Asia-Pacific region at the International Air Transport Association (IATA), told Al Jazeera.

British Airways, Singapore Airlines, Malaysia Airlines, Qantas, Germany's Lufthansa and Air France-KLM were among airlines charting new routes to go around Iraq and Iran.