“'What's all this rushing about in aid of', then?” [=what's all this rushing about for?] “We're trying to get things ready for the boss's visit.”
The teacher enlisted/sought the 'aid' of several students for the project. [=the teacher asked several students to help with the project]
When the climbers became trapped by bad weather, a rescue party was sent 'to their aid'. [=was sent to help/rescue them]
(..) that earlier this evening... Harry Potter was sighted in Hogsmeade. Now... should anyone... student or staff attempt to aid Mr. Potter? They will be punished in a manner consistent with the severity of their transcription, further more... Any person found to have knowledge of these events... (..)2011 Harry Potter and the Deathly Hallows: Part 2