I can only speak of parking at JFK. Would that be an option for you? We have parked long term at JFK numerous times. I know at JFK (not sure if availa for all airlines, but is for JetBlue) you can "reserve" a spot in an off-site lot.
Per JetBlues website (LGA and JFK below it):
Parking - LGA
*All rates are subject to change without notice.
daily parking
The Parking Garage and Lots 1, 4, 5, 6 & 7 are *$3 for the first half hour or part,
*$6 for up to 1 hour, and *$3 for each hour or part thereafter with a maximum rate
of *$24.00 for each 24-hour period.
Daily lots can be used for up to 30 days parking at the posted daily rate. No
long-term reduced rates are offered in the daily parking lots.
Parking - JFK
Availability of parking can be checked over the phone at 1-718-244-4080. If you
have any questions related to parking at JFK, please call the parking lot operator
at 1-718-244-4168.
* All rates are subject to change without notice.
AviStar parking
AviStar's Airport Parking center is located just minutes away from JFK.
Reservations are required for AviStar parking at JFK. Arrive at the facility,
park and the AviStar Airport Parking 24-hour shuttle service will save you time by
taking you from your car door to your departing terminal.
AviStar phone number: 1-800-621-PARK (7275)
Directions to AviStar Parking:
From the West (New Jersey and Staten Island):
New Jersey Turnpike to Exit 13 to Goethals Bridge/Staten Island Expressway.
Stay on the Staten Island Expressway to Verrazano Narrows Bridge. From the
Verrazano Narrows Bridge follow the signs to the Belt Parkway East. Stay on
the Belt Parkway East following signs to Kennedy Airport to Exit 19 (Kennedy
Airport/Lefferts Boulevard). At the bottom of the exit ramp turn left onto Lefferts
Boulevard and then immediately right onto South Conduit Avenue. Stay on
South Conduit Avenue approximately ¾ mile and the AviStar entrance is on the
right at the corner of South Conduit and 130th Street.
From the East (Long Island):
Take Southern State Parkway to the Belt Parkway West. Stay on the Belt
Parkway West to Exit 21A (Rockaway Boulevard). This exit will put you on
North Conduit Avenue. Stay on North Conduit Avenue approximately two miles
to 130th Street and make a left onto 130th Street. At the first traffic light make
a left onto South Conduit Avenue and the AviStar entrance is immediately on
the right.
From the North (Grand Central Parkway, Connecticut and Whitestone Bridge):
Take the Van Wyck Expressway South to the Belt Parkway West/ Verazanno
Bridge exit. This will put you on North Conduit Avenue. Stay on North Conduit
Avenue to 130th Street and make a left onto 130th Street. At the first traffic
light make a left onto South Conduit Avenue and the AviStar entrance is
immediately on the right.
long-term parking
Long-term parking is *$15 for up to 24 hours; *$5 for each 8 hour period or part
after the first 24 hours.
The long-term parking lot is four miles from the Terminal area. A 24-hour
complimentary shuttle service operates between the parking lot and each of
the terminals every 15 minutes between 6:00 a.m. and midnight and every 30
minutes between midnight and 6:00 a.m.
