320 Two-Engine Plane
General Information
The following information has been collected from original newspapers, catalogs, and magazines, some of which are freely available for reference below. The rest can be found in the site’s gallery. No aggregate catalogs (BrickLink, Brickset, etc.) were used.
Instructions: H-2305
Advertised Part Count(s): 123 pieces
First Year Confirmed Available: 1967(USA)
All 1967 Model Makers are incredibly hard to track as they were not typically advertised like the larger assortments/models. However, the 320 is fortunate to have a 1967 appearance:
I'll come back with better Canadian sources later, but we at least know the set was available in Canada.
Most Likely Retirement Date: 1969(USA)
The set does not appear in a 1970 dealer catalog but does appear in the 1969 idea book, thus it was likely retired in 1969.
Last Year Seen Available: 1970
Newsday Suffolk Edition, August 17th, 1970
Aliases: Two-Engine Plane, Two Engine Airplane
Retail Price(s): $1.00-$2.29(USA)/$????(Canada)
Note: Samsonite discontinued listing RRPs for sets in 1967. As a result, Model Maker sets' prices can vary. I've theorized this to be a reason 1968+ Model Makers include a secondary number, you can read about it here.
Rarity Score(Index): 4/7
Known Box/Packing Variants
There are two known versions of the USA 320:
The drawer version without an alternative number:
Around 1970, Model Makers were given a tabbed box and an alternate number:

There should exist a Canadian version of the box. It will be a tabbed box and not a drawer/sleeve style.
Box/Overview
The 320 Two-Engine Plane, like all sets in the new Model Maker line, was not an original Samsonite creation but instead already was a set sold in Europe.
The North American version reuses the European image of the set:
And the sides are the standard affair with other 1967 Model Makers:
And the drawer(or tab on later boxes):
Contents
The set contains standard elements that were in Samsonite's part inventory in 1967. My copy needs sorted out so I do not have a contents image at the moment.