Sunday Times

[janrei]

Think I have some answers but can't figure out why. 24a. Retiring officer engaged in boring work? What a laugh! Is it chortle? 28a. Author's short book about most of Swiss city.t?r?e?e?
17d. Fancy planes might be flown thus? (2,5) ?y, ???r?e. The only thing I can think of is 'by George' but doesn't make sense.
20d. business raised some support with unknown people (6) o???p?

[frugalfred]

24 yes. chore round lieutenant, lt, reversed

[Neveracrossword]

24 Yes, Chortle - Chore, boring work, with TL (LT, lieutenant, reversed - ie retiring officer).

[dominie]

Chor tl e
Turgenev
By George
Occupy

[bookbinder]

17d George is a jokey name that airline pilots use for the automatic pilot. If a plane is on automatic pilot, it is being flown by George.

[scorpiojo]

Chore (boring work) around Lt (Lieutenant) reversed
Tur Genev(a)
By George (the autopilot)
Occupy - Co (business) reversed + cup (support) + y (unknown)

[THEMOTLEY1]

By George, george was the auto-pilot in the film Airplane

[Tilly2]

28a Turgenev