What Callsign: Smurf says is quite true and correct. We don't happen to have a spread sheet that details the lengths of the ship minis. Most are designed to fit a single standard 1-inch hex base flight stand that is quite ubiquitous in the industry and tend to be a bit over one inch in length and/or wingspan/width.
For example, note the size of the ship minis in the attached photos to the flight base. Keep in mind that the flight base is 1 inch across from one flat side to it's opposite flat side.
Note that the Warhounds (escort class vessels) like the Narwhal military transport shown here sit on two stands and occupy two hexes on the game board.
Hopefully this answers your question!
"Pathetic earthlings. Hurling your bodies out into the void, without the slightest inkling of who or what is out here..."
- Ming the Merciless