Yes, it is possible to book last-minute flights online. Many airlines and travel websites offer the option to book flights close to the departure date. However, there are a few factors to consider when booking last-minute flights:

1. Availability: Last-minute flights may have limited availability, especially during peak travel periods or for popular routes. It’s important to be flexible with your travel dates and be prepared to choose from the available options.
2. Price: Last-minute flights can be more expensive compared to booking in advance. Airlines often increase prices for last-minute bookings due to higher demand or limited availability. However, there can also be occasional deals or discounted fares for last-minute travelers, so it’s worth checking different airlines and travel websites to find the best options.
3. Flexibility: Last-minute bookings require flexibility in terms of travel dates, times, and even destinations. Being open to different airports, routes, or connecting flights can increase the chances of finding suitable options at short notice.
4. Comparison and alerts: Utilize flight search engines or travel websites that allow you to compare prices across multiple airlines and set up fare alerts. These tools can help you find the best deals or notify you when prices drop for your desired route.
5. Online travel agencies and mobile apps: Online travel agencies (OTAs) and mobile apps often offer last-minute flight deals and can provide convenient options for booking on short notice. They may have special offers or discounted fares for spontaneous travelers.

While booking last-minute flights online is possible, it’s important to be aware of potential limitations and higher costs. It’s advisable to be prepared for different options, set a budget, and be flexible with your travel plans to maximize the chances of finding suitable flights at short notice.