DUBAI- Dubai International Airport, the world's busiest airport for international travel, closed its airspace for 69 minutes due to unauthorized drone activity on Saturday, causing 22 flights to be diverted, aviation authorities said.Government-owned Dubai Airports, which operates Dubai's two main airports, said in a statement the closure lasted between 11:36 a.m. and 12:45 p.m., and Dubai Airports chief executive Paul Griffiths said thousands of passengers suffered disruption to their journeys.Sixteen of the diverted flights went to Dubai World Central, Dubai's other main airport, a Dubai Airports spokesperson told Reuters. Dubai, a trade, tourism and investment hub for the Gulf region, is one of seven emirates that make up the United Arab Emirates (UAE)."This is a very serious incident and we obviously take the safety of our customers and our staff extremely seriously," Griffiths told Dubai's Dubaieye 103.8 radio."As you can imagine, this is the busiest international airport in the world and there was major inconvenience to thousands of passengers ... There are very clear restrictions and no fly zones around all airports in the UAE, saying that this type of activity is actually illegal."The flying of drones is prohibited within 5 km (3 miles) of airports, helipads, landing areas or manned aircraft in the UAE.