Up in the Air

[fleurbird]

Any clues greatly appreciated
37 Speed and skill needed on pole with this vehicle (10) I have hovercraft but not sure.
52 Play the fool after a sheet was changed (3,7) I know it's anagram of asheet+another word for fool but can't crack it.
73 Frolic and there's likely to be a song in the air (4,5) ?Lark something
78 The last unprincipled person has a parachute 6 I know it starts with D but then stuck.
Many thanks.

[Dinkypuzzled]

37. speed is pace.
52. I discovered that to 'gull' is to deceive.
78. try rogue.

[Harry-Wragg]

52 The play is The Seagull

[fleurbird]

Many thanks both of you. I'd tried rogue but will try again. Never heard of gull in that context. Good to learn! Will work on pace.

[johnalex]

73. Lark about (play boisterously, frolic)

[fleurbird]

Many thanks. I had lark but couldn't think of second word!

[Green Sal]

Someone else had offered Lark about for 73 when I asked - I think I must be missing something, because this is still the only one that I don't understand! I got Lark quite early on, but can't see the relation of the second part of the clue to lark about? Or am I trying to make it more difficult than it is? Any help appreciated!

[sheeee_ra]

has anybody answered Green Sal and offered a definitive explanation for Lark About....

its the answer I had although can see Green Sals point...its not the most convincing of questions if the answer is correct...