“Oh!  Frank’s provided for that, and besides, we don’t really expect to round the thieves up, just find out if they’ve dropped down anywhere inside of thirty miles to the north of Bloomsbury.  Shall I get aboard, Frank?”

“Yes; and after we’re off, Larry, will you and Elephant do me the favor to step around to my house, and tell my folks that the Bird boys have hired out as scouts to Chief Waller?  Tell dad that we’ll be mighty careful, and for mother not to worry about us.  You know I always call Aunt Laura mother, because she’s been that ever since my own died years ago.  Will you do that, boys?” and Frank sitting there ready to start, turned a smiling face upon his two friends.  Even as they promised, the aeroplane started off, and a minute later soared up in the air, like a bird rejoicing at its freedom for leaving the earth behind.

CHAPTER VIII

JUST BELOW THE CLOUDS

“Good luck to you, boys!” came floating up from the ground, above the buzzing of the busy little Kinkaid motor; and looking down, they could see Larry, Elephant, yes, and the old veteran also, carrying on excitedly, as they swung their hats around.

“Who’re you waving your handkerchief to, Frank; does your best girl keep her eyes on the skies all the day long, looking to see you come around?” demanded Andy, humorously.

“Yes, that’s my best girl, as sure as you live; and she’s standing there on the porch of our house right now, waving to me—­Aunt Laura, who thinks just as much of me as any mother could.  But Andy, neither of us said anything when Larry told about that hobo aviator named Casper Blue; yet he answered the description the bank watchman gave of the smaller man who had a stiff arm.”

“Oh, I noticed that, all right, even if I didn’t look your way,” returned Andy, promptly.  “It sort of clinched the nail we drove through didn’t it, Frank?”

“Seems like it,” the other went on to remark.  “And the chances are ten to one, we’ve got the story down fine right now, know who one of the robbers was, why they wanted to steal an aeroplane to make their get-away in, and all that.  But there are a few things we don’t know, that’d throw a little more light on the affair.”

“As what?” queried his cousin.

“Well, for one thing, the Chief seemed to think the thieves might have had inside information, they seemed to know so much about things connected with the bank, our having an aeroplane, where we lived, what our habits were, and then about Percy’s biplane in the bargain.  Now, that’s something serious; if there’s a man in Bloomsbury who’s in league with such rascals he’ll be apt to help them out again later on if they get away with this job; and he ought to be found out.”

“Whew! looks like we’ve got a big job on our hands if we hope to do all that sort of thing,” commented Andy, with a whistle to indicate his feelings.