[M T]

Conversely, an antenna on a plane at 40,000 feet could impact GPS (jam or spoof) surface (and air) regions up to 400km.
And, of course, we're talking about the public GPS.  
Against a device that can understand the military GPS (do we supply such devices to Ukraine?), the spoofing presumably won't work, but jamming still could.  With a directional antenna array, a device can do better against jamming.

[M T]

Conversely, an antenna on a plane at 40,000 feet could impact GPS (jam or spoof) surface (and air) regions up to 400km.
And, of course, we're talking about the public GPS.  
Against a device that can understand the military GPS (do we supply such devices to Ukraine?), the spoofing presumably won't work, but jamming still could.  With a directional antenna array, a device can do better against jamming.