Thanx all, great help!
The crew/craft are from the moviegoers' present - say early '08 - so 2063 or thereabouts.
A better synopsis (remember, bleedin' raw) :
The year - 2008. Post-911 tensions and conflict have increased such that the world teeters on the brink of nuclear armageddon.
Against this grim backdrop --- a commercial flight - CFL2314 -departs PHX for ATL, all progressing per routine until the flight abruptly vanishes from ATC scopes - leaving no trace, no clues, nothing to assist subsequent investigations whatsoever.
On the volatile stage of global politic, certain key players of zero ethic see the flight's thorough loss as opportunity to forward agenda - and cities vanish beneath mushroom clouds.... Fade to Black
Fade In : Flight 2314 continues an uneventful climb to altitude per last clearance.
Cue the first indications of situation breakdown: instruments offer anomolous data, comm equipment offers nothing, etc...
Enter bizzare aircraft - hushed and sinister, effortlessly gliding into scene and fixes dark attention upon an unwitting 2314 - post-apoc military responding to intruder threat.....
To prevent this post from ballooning into novel size (very real possibility if I am unchecked) --- a more-informed crew is confronted with the task of communicating peaceful intent sans relevant equipment and utterly ignorant of existing intercept protocols. This is attempted through purposeful maneuvering of their a/c in such a way as to gain/maintain non-lethal attention of pertinent parties - much in the manner bees use patterned flight to convey messages. Hence my interst in the depth/degree of interpretation possible with little more than primary track
available. The referenced 4nm segment was example only - no stone carving here, for sure. Is there a method by which a (more realistic) discrepancy between ground speed and distance travelled can be used to extrapolate altitude change?
Thanx,
Stephen