The main issue is not the phone so much as the shooting conditions: cockpit reflections, window layers/coatings, and aircraft vibration.

What helps most:

• Block stray light between the phone and the window. A rubber lens hood is probably the best simple accessory for cockpit use. A black cloth around the phone/window area can also help.
• Keep the phone as close to the window as practical to reduce reflections.
• Stabilize as much as possible. A gimbal may help, especially if the phone uses longer exposures.
• If your phone allows it, shoot RAW so you have more flexibility to improve contrast and color later.

Limits to expect:

• Aircraft windows can cause extra reflections because they may have multiple layers, spacing between panes, coatings, or scratches.
• Vibration and movement make very long exposures difficult, so results may still be limited compared with ground-based night photos.

In short: the best improvement is aggressively controlling reflections with a rubber hood or dark cloth, then using the steadiest setup possible and editing a RAW file afterward.