Upgrading at the airport

I have been waiting for a G seat to pop up for my return flight from ATL to LHR but unfortunately there hasn't been one for me this time. :(

Is it possible to upgrade at the airport with miles if there are seats available or does there need to be a G available for this?

Also is someone please able to do a load check on my flight please 11th Jun - VS116.

Thanks, Phil

VS 116 0 ATL
11/06/16 8:40 PM LHR
12/06/16 10:00 AM 333
Daily
53% / 21m J5 C5 D5 I4 Z4 W3 S1 H1 K0 Y9 B9 R9 L9 U9 M9 E9 Q9 X5 V3 N2 O0

David

It is often possible to upgrade at the airport if there are spare seats, even if no Gs were available.

With only 5 seats left in J, though, and with ATL being a popular business route with last minute bookings commonplace, it may well sell out. There may be no shows on the day though.

Just because there may be seats available does not mean that VS automatically makes them available to be upgraded using miles (or even cash) at the airport but it does no harm in asking.

And just to stress that J5 doesn't mean there are 5 spare seats. It only means that VS are willing to (over)sell 5 more business seats.

I have seen V offer upgrades at the boarding gate.
So if you get rebuffed at the desk, you can always ask again.