Unless the air-raft has a pressurized cabin, you *can't* use it for a
trip into space that lasts more than a day. and that would be one
*miserable* day.

There's the not so small matter of waste management. Urine is easy,
especially you are male. If you are female, it's still doable, just
less comfortable.

But "Fecal Material" has no good solution until you get something
along the lines of "nanites". Untuil then the *only* solution is
essentially a diaper.

In fact, disposable diapers are a spin-off of the Apollo program!

Sitting in your own $#!+ for days is a non-starter.

A pressurized cabin lets you avoid *that* problem.

But for interplantary travel, the real show stopper is radiation. If
there's a solar flare, everybody in the air raft is *dead*. If not
immediately, then within hours. Very unpleasant hours.

And even "normal" radiation levels in interplanetary space aren't
good.

Ships and "small craft" have shielding against this. Air rafts don't.

Oh yeah, you'll need that shielding if you are in the Van allen belt
equicvalent of a planet for an prolonged period. And you'll
*definitely need it when scooping fuel from a gas giant. The
radiation belts around Jupiter are lerthal as far out as Europa,
maybe farther (Ryk Spoor had to do a lot of work to let some
characters survive after a forced landing on Europa in one of his
books)

--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com