It was 42 degrees and raining lightly around 3 a.m. on Monday when an inebriated off-duty employee for a government intelligence agency decided it was a good time to fly his friend's drone, a 2-foot-by-2-foot "quadcopter" that sells for hundreds of dollars and is popular among hobbyists.

But officials say the plan was foiled, perhaps by wind or a tree, when the employee — who has not been named by the Secret Service or charged with a crime — lost control of the drone as he operated it from an apartment just blocks from the White House....