The skies have become so crowded with unmanned aerial vehicles (UAVs), otherwise known as drones, that they are posing a big problem for the world's air traffic controllers and aviation authorities who are scrambling to draw up new laws and systems to accommodate them.
"Its not just a problem it's THE problem and the main thing holding back UAV development," said Gareth Jennings, the aviation desk editor at IHS Janes, the defence journal.
The number of UAVs being deployed by military and commercial operators has risen exponentially in recent years.
At this week's Idex in Abu Dhabi an entire wing has been devoted to the technology with scores of manufacturers on display.
But each of them, while celebrating the unprecedented success of their nascent industry, seemed quietly concerned about the future of regulation surrounding unmanned aircraft.
"There are some real challenges ahead for the UAV market, said Andrew Duggan, a managing director with Insitu, a wholly-owned subsidiary of Boeing that develops UAV technology.
"Firstly there is the sense-and-avoid problem to solve. Whereas the last great fallback for a pilot is to look out the window to see a potential collision, a UAV can't do that."
Teal Group, the US defence analysts, estimates that global spending on UAV technology will almost double in the next 10 years from US$6.6 billion (Dh24.24bn) today to about $11.4bn a year.
"The UAV market will continue to be strong despite cuts in defence spending," said Philip Finnegan, Teal Group's director of corporate analysis.
"UAVs have proved their value in Iraq, Afghanistan and Pakistan and will continue to be a high priority for militaries in the United States and worldwide."
Teal Group also predicts that the United States will account for 62 per cent of the worldwide spending on UAVs in the next 10 years.
In response to the concerns, the US government last week issued a new law designed to eventually integrate drones and UAVs into the country's commercial airspace. There is a 2015 deadline to complete the project. Since then the US federal aviation authority has identified six test sites across the country to begin evaluating how UAVs will affect air traffic.
Raytheon, the US defence giant that has worked with Dubai airport on its new air traffic control system that is expected to go live within weeks, is also working to address the challenges posed by UAVs.
"Safety remains the highest priority. Pilots and controllers need to accurately track the location of other vehicles to avoid the possibility of collisions," Raytheon said.
Raytheon has developed a system to be used in the US that it believes will help relieve concerns.
"Our solution provides the federal aviation administration and the department of defence with a cost-effective and safe approach to handle the thousands of unmanned aerial systems that will be flying in our airspace in the next few years," said Joseph Paone, the vice president of air traffic management for Raytheon's Network Centric Systems business.