Didymus mulled that over for a few seconds before nodding. "I have never engaged in battle against a foe in the air or by sea," he admitted with a frown. So he would not have the first clue how to prepare for such a battle.
"I wonder which of our brethren might know of such things," he added, scratching his head as he thought. "Perhaps Sir Harry mayest have knowledge of attacks from the air. He knoweth much of the Dementors, and those creatures hath the power of flight."