Here's why Tempe's July 4th drone show didn't happen as scheduled

Heat a factor in canceled Tempe drone show
Tempe city officials are speaking out, after a 4th of July drone show at Diablo Stadium had to be canceled.
TEMPE, Ariz. - Officials with the City of Tempe are speaking out, after the city's July 4th drone show did not take place as scheduled on Friday.
The backstory:
The city had originally scheduled a drone show at Diablo Stadium, and the show was sold-out.
The drones, however, never made it up into the air. While the drone show didn't take place as originally planned, the crowds did get to enjoy a traditional fireworks display. The display was originally scheduled to take place following the drone show.
What they're saying:
In a statement, Tempe city officials said the contractor had difficulties with equipment that overheated.
City of Tempe's statement regarding the abortive drone show
"We were honored to host a sold out 4th of July celebration for our community. Unfortunately, our contracted drone operator experienced technical difficulties due to overheating equipment and the drone show was unable to go on. We apologize for any disappointment attendees experienced and hope everyone enjoyed a wonderful evening of family activities and a spectacular fireworks show."