Question : How long do most people visit Reykjavik?
Answer : Of course you're not most people, but if you were, you'd stay roughly two days.
Question : Would you be willing to change your travel days if it saved you money?
Answer : For the month of October, Thursday is your cheapest day to fly. Being flexible with your travel days garners even more savings during booking.
Question : Is there another local airport that can get you to Reykjavik?
Answer : Lucky for you, there is another airport near London. London Heathrow Airport (LHR) is 22 miles away, and over the next few months, flights are being priced 72% cheaper than flights from London City Airport.