You’ve probably done this. You land at the airport at seven in the morning, on the good flight, the one that gets you into the city with a full day still ahead of you. Except your Airbnb isn’t ready until four in the afternoon. So now what? 1. The four ways travelers currently handle it Book an extra night, just to guarantee an early check-in. This works. It’s also the most expensive way to close a nine-hour gap — a full night’s rate, mostly unused, just to buy certainty.   Find a luggage storage service nearby. A reasonable middle ground,…