Airbnb forecast third-quarter revenue below estimates on Tuesday and warned of shorter booking windows, suggesting travelers were waiting until the last minute to book due to economic uncertainty, sending its shares down 15% after the bell.Domestic travel in the United States has been pressured since the start of the year as more Americans have grown cautious about travel spending on worries about the health of the US economy.San Francisco-based Airbnb reported quarterly profit of $555 million, or 86 cents ...