Possible Clues:

• Emergency helicopter operation
• Fly people or goods to places not otherwise accessible
• If trail is vandalised, supplies by plane
• Transport by means of glider?
• Way to counter being cut off if trial must be rearranged
• Strain appropriate in rescue
• Emergency delivery, of a sort
• Send in via helicopter, maybe
• Evacuate by helicopter, say
• Primarily, as in real life, it's fantasy that provides a means of escape