British Airways’ PR team emailed me about a 2-day business class sale with fares starting at $2,015 (including taxes, fees and carrier charges) roundtrip to London.

The key is that this sale fare stacks with several other discounts to make it pretty amazing.

The sale is available through 11:59pm Eastern on Friday, October 16. It requires a Saturday night stay. Here are key terms:

..select “I” class fares for travel November 16, 2015 through August 31, 2016 (with all travel completed by August 31, 2016) from select U.S. gateways to London on British Airways or American Airlines operated services, only. Flights to and from New York-JFK are not included for travel December 1 through December 13, 2015, flights to and from New York-EWR are not included for travel November 16, 2015 through December 20, 2015, flights to and from San Diego (SAN) are not included for travel November 16 through November 29, 2015, flights to and from San Francisco (SFO) are not included for travel November 16 through November 22, 2015, and flights to and from Baltimore (BWI) are not included for travel January 4 through February 14, 2016. Flights to and from London City (LCY) are excluded from this promotional offer.

Thankfully the $400 AARP member discount on British Airways business class is back.

AARP members save $400 on British Airways business class tickets. Anyone can join AARP instantly for $16 per year.

That discount stacks with the 10% off discount given to British Airways Visa Signature cardholders using promo code CARDOFFERU.

The British Airways Visa Signature card comes with a huge signup bonus: Earn Total of 100,000 British Airways Avios

When searching with the AARP discount I was only given the option for economy queries. I left it that way, and economy and business class both came up to choose from.

After selecting flights, the next page gives you an option to click a radio button and expand where you will enter a promo code or eVoucher.

Note that if you book an American Airlines codeshare traveling on British Airways, you’ll earn American’s premium fare bonus. I fares originally earned bonuses only for elites:

However in May they improved earning on discount business class I fares for general members.

Unfortunately the American Airlines flights may not stack with the 10% British Airways discount.

Either way register for American’s transatlantic bonus and roundtrips through January 31 earn 25,000 bonus miles.

Stacking the British Airways AARP discount with the 10% British Airways Visa Signature Card discount here’s the roundtrip price:

However you can book these flights for even less!

Through October 19 paying part of a fare with British Airways Avios is worth 2.5 times the normal value per point. So that offer stacks with the fare sale and with the AARP discount.

It is still a normal paid ‘I’ discount business fare so the standard fare rules apply and the ticket accrues miles even when you partially pay with Avios.

And it really does price at $646!

British Airways points can be obtained via instant transfers from American Express Membership Rewards (at less than full value) and Chase Ultimate Rewards.

Unfortunately there is no way to stack the pay with cash and Avios discount with the 10% British Airways Visa Signature card discount. But let’s not be greedy..