Jetblue - Seats
This is the official policy on the exit row. Unlike other carriers, there is no mention of seat belt extenders making the traveler ineligible to sit in the exit row, although the crew has the final say on whether someone is eligible to sit there.
Emergency exit row requirements
Emergency doors are often heavy and awkward to lift, push, pull and maneuver when opening. For the safety of all customers, federal regulations require that the customer seated in an emergency exit row be able to assist the crew in the event of an emergency.
All customers sitting in the exit row must be willing and able to meet the following exit row requirements:
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Airport customer service crewmembers will make the final decision in determining who will be seated in exit row seats, even when seats have been assigned prior to arrival at the airport.
Length of Seatbelts
Our seatbelts are 45 inches in length and you can request 25 inch extensions onboard the aircraft.
Although there is an implied, but not explicit rule against using extensions on airbag equipped seat belts.
Airbus A320
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A320 aircraft, numbered N784JB and higher, come equipped with an airbag seatbelt for each seat in rows 1-5 and 10-12. The airbag is designed to inflate towards the center of the customer providing maximum protection against injuries that may occur in high g-force events. Please note: seatbelt extensions will deactivate the airbag seat belts.
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Identical wording is included under the A321 section.