The Hubble isn't flying through the atmosphere, and is specifically engineered to take very long-duration exposures.
You've seen the Hubble Deep Field image, right? The one where Hubble's operators found an entirely empty region of sky and stared at it for over 134 hours over ten days and 342 exposures (mostly separated to keep individual exposures from being degraded by cosmic ray strikes).
That's really not comparable with an aircraft, moving through the atmosphere, with turbulence, engine vibration, and other factors contributing to deviations from a steady trajectory. Though the image does appear to be fairly plausible from others' comments.
The question was about why there weren't streaks from the long exposure photo. My point is that the hubble also moves very fast and takes long exposures of tiny points of light without streaks. Streaking has very little to do with the atmosphere and more to do with moving the target around the sensor during exposure.
The hubble is above the atmosphere to reduce other kinds of optical interference, but streaking isn't one of them.
Any vibration or relative movement of either the camera or aircraft will also cause movement trails, though not the ones typically associated with long exposures and star trails centered on the North Star.
Most such long exposures span at least several minutes, though.
It's less a matter of cost and more of its situation: orbiting, not flying, through vacuum, not air, with careful attention to stabilization and vibration elimination.
It costs a lot of money to get that large of an object into that ideal location, though. In the context of my original comment, "cost" could be seen as a proxy for "difficulty" of any kind. Perhaps it was too short and a bit flippant, but it seemed appropriate to respond in kind to the original comparison between Hubble and an airplane.
There are also aircraft-based observatories. Principally for exploring specific wavelengths of light absorbed in the lower atmosphere. And, incidentally, rather less expensive than orbital observatories.
Good guidance, getting above turbulence, and having specific compensation for movement/motion all helps.
My points stand: the characteristics of Hubble are not directly related to cost, and attributing the distinction to that alone is a poor explanation.
