航空公司超賣機位，其實是一種長期存在且相當常見的營運策略。從航空公司的角度來看，一架飛機如果出現空位，就等於資源被浪費，因為飛機起飛的成本幾乎是固定的，不會因為少一位乘客而降低。因此，為了避免這種空位損失，航空公司會根據過去數據，預估有多少旅客可能臨時取消或沒有報到（no-show），進而適度多賣一些機位，來提高整體載客率與收益。延伸閱讀：《知識》機票定價策略 – 距離起飛時間越近的機票為什麼越貴？
例如商務旅客常常臨時更改行程，轉機旅客也可能因為前段航班延誤而錯過飛機，這些都會導致座位臨時空出。為了填補這些不確定性，航空公司才會選擇超賣機位。在美國，這種做法是合法且受到監管的，因此已經成為航空業的常態運作方式。
不過，再精準的預測也難免出現例外。有時候所有乘客都準時報到，這就會導致「人比座位多」的情況。當這種情況發生時，航空公司通常會先尋找「自願者」，提供現金補償、住宿或旅遊券等誘因，請部分乘客改搭下一班飛機。如果一開始沒有人願意配合，補償條件往往會逐步提高，直到有人接受為止。
但如果即使提高補償仍然不足，就會進入所謂的「非自願拒載」，也就是由航空公司決定哪些乘客需要讓出座位。這時候，航空公司通常會依照一套內部規則來排序。像是較晚完成報到的乘客，通常風險較高；購買較低票價（例如基本經濟艙）的旅客，也比較容易被調整；而高價艙等或彈性票的乘客，則通常會被優先保留座位。
此外，會員等級也是重要因素。經常搭乘的高等級會員，因為對航空公司價值較高，通常會受到較好的保障。行程安排同樣會影響決策，例如有轉機或多段航班的旅客，一旦被取消座位，可能引發後續一連串的問題與成本，因此航空公司通常會優先保留這類乘客。相較之下，單純直飛、且行程較容易調整的旅客，被選中的機率就相對較高。
部分特殊族群也會被優先保護，例如家庭旅客、未成年單獨旅行者或有特殊需求的乘客，避免造成更複雜的狀況。因此，有時候反而是單獨旅行的旅客，更容易在超賣情況下被調整行程。
航空公司也開始透過科技來降低超賣帶來的影響。Volantio 是一家來自美國亞特蘭大的旅遊科技公司，專注於提供「訂票後（post-booking）」的收益與運能優化解決方案。他們運用 AI 與機器學習分析航班需求與乘客行為，主動找出行程較有彈性的旅客，並提供誘因鼓勵他們調整航班。導入 Volantio 服務的航空公司，通常會在起飛前幾天就先詢問乘客是否願意改搭其他航班，並附上相應的獎勵。
這樣的做法，讓航班調整可以提早發生，而不是集中在登機前的最後一刻，不僅減少現場的混亂與壓力，也讓旅客有更充裕的時間與彈性做出安排。
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Why Do Airlines Overbook Flights?
Overbooking is a common and long-standing practice in the airline industry. Simply put, an empty seat means lost revenue. Since most flight costs are fixed, flying with one fewer passenger doesn’t save much money. To avoid this, airlines use past data to estimate how many people might cancel or not show up, and then sell a few extra tickets. This helps keep flights as full as possible and improves overall revenue. Read More: Why Are Flights More Expensive Closer to the Departure Date? Understanding Airline Pricing StrategiesFor example, business travelers often change their plans at the last minute, and connecting passengers may miss flights due to delays. These situations can leave seats empty. Overbooking helps airlines handle this uncertainty and reduce the chances of flying with empty seats. In places like the United States, this practice is legal and regulated, so it has become a normal part of airline operations.
Of course, forecasts aren’t always accurate. Sometimes, everyone shows up, and there are more passengers than seats. When that happens, airlines usually start by asking for volunteers. Passengers who are willing to take a later flight may receive compensation, such as cash, hotel stays, or travel vouchers. If no one accepts at first, the airline will often increase the offer until someone agrees.
If there still aren’t enough volunteers, the airline may need to deny boarding to some passengers. This is known as “involuntary denied boarding.” Airlines follow internal rules to decide who is affected. Generally, passengers who check in later or buy cheaper tickets (like basic economy) are more likely to be selected. Those with higher fares or flexible tickets are usually given priority to keep their seats.
Frequent flyer status also matters. Passengers with higher status are often better protected. Travel plans play a role too; people with connecting or multi-leg trips are usually prioritized, since changing their flights could cause bigger disruptions. On the other hand, passengers on simple, direct flights with more flexible schedules are more likely to be rebooked.
Some groups are also given extra protection, such as families, unaccompanied minors, and passengers with special needs. Because of this, solo travelers may be more likely to be affected when flights are overbooked.
To make this process smoother, airlines are increasingly using technology. Volantio, a travel tech company based in Atlanta, focuses on “post-booking” optimization. It uses AI and machine learning to analyze passenger behavior and identify travelers who may be open to changing their plans, then offers them incentives to switch flights.
With tools like Volantio, airlines can reach out to passengers days before departure, instead of waiting until boarding time. This reduces last-minute stress at the airport and gives travelers more time and flexibility to adjust their plans.
