What does "Moth" mean here in Agatha Christie's Peril at End House?

'George hasn't turned up,' said Nick. 'A nuisance his having to go back to Plymouth last night. He'll get over this evening sometime or other, I expect. In time for the dance anyway. I've got a man for Maggie. Presentable, if not passionately interesting.'

A faint roaring sound drifted in through the window.

'Oh! curse that speedboat,' said Lazarus. 'I get so tired of it.'

'That's not the speedboat,' said Nick. 'That's a sea-plane.'

'I believe you're right.'

'Of course I'm right. The sound's quite different.'

'When are you going to get your Moth, Nick?'

'When I can raise the money,' laughed Nick.

'And then, I suppose you'll be off to Australia like that girl-what's her name?'

'I'd love to-'

'I admire her enormously,' said Mrs. Rice, in her tired voice. 'What marvelous nerve! All by herself too.'

'I admire all these flying people,' said Lazarus. 'If Michael Seton had succeeded in his flight round the world he'd have been the hero of the day-and rightly so. A thousand pities he's come to grief. He's the kind of man England can't afford to lose.' (Peril at End House, Agatha Christie)

I suppose Moth here refers to an expensive brand/thing but can't figure out exactly what. The phrase in question is bolded.

Solution 1:

The de Havilland Moth was a line of airplanes manufactured in the 1920's and 1930's.

Since they are talking about airplanes, and the book was published in 1932, that may be the answer.

According to Wikipedia:

Every light aircraft flying in the UK was commonly referred to as a 'Moth', regardless if it was de Havilland-built or not.

Solution 2:

As alternative to the sailboat mentioned by Helmar, it could refer to the De Havilland Tiger Moth, a popular biplane used as a trainer from 1931 into the '50s. Al Stewart's "Flying Sorcery" sings of

You were taking off in Tiger Moths,

Your wings against the brush strokes of the day.

In this case, "your Moth" would be a familiar contraction. Since "Peril at End House" was published in 1932, the timing fits (although just barely).