The plurality of commercial aircraft in flight at any given time provides extensive geographic coverage including {HEAD ~ areas} currently unserved or underserved by {TAIL ~ terrestrial cellular systems} 
currently underserved by
The plurality of commercial aircraft in flight at any given time provides extensive geographic coverage including { HEAD ~ areas } currently unserved or underserved by { TAIL ~ terrestrial cellular systems }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL