What is a "conventional engine"?

i repeatedly stumbled across the term "conventional engine", mentioned for
example in the entry of the elven flitter ("adventures in space" , p.15):
"Landing craft: sometimes owners strip the spelljamming engine out of a
flitter and replace it with a MORE CONVENTIONAL ENGINES. in this
configuration, the flitter is useless for interplanetary voyges, but
suitable for short hops into and out of the athmosphere or between ships.
the elven navy follows a strict policy of only allowing ships without helms
to make landfall, so this use of flitters as landing craft is very
common."

the term was mentioned in other entries as well, but i found no explanation
just what these "conventional" means are! obviously it´s no other helm,
since that would enable interplanetary voyages. while a can imagine gnomes
using giant spacehamster- driven running wheels (...and an minor helm
hidden among the pipes, bells and whistles *g*) or even alchemical stuff
(smokepowder comes to mind... *shudder*), i can´t see what elves (or other
racs, for that matter) use.

- perhaps a spell of flying could be cast on the ship?
- or something completely unmagical. but what exactly?

...or did i overlook something obvious? wouldn´t be the first time. ;)

another thing that bugs me: does the elven flitter move its wings when
flying? the name implies that, but i didn´t read a description yet. the
same goes with the dragonfly, damselfly or wasp: do their wings move or do
they just "glide"?

i am for the moving-wings- version, because the description of the flitter
states that it can go OUT of an atmosphere, which would be kind of
difficult with a glider- the pilot would have to rely on upwinds that
actually blow his ship out of (!) the athmosphere.

Tauster