A codeshare flight is an agreement between airlines where one carrier operates the flight while another markets it under its own flight number. This allows airlines to expand their networks without operating additional routes, giving travelers more flexibility in booking flights. For example, a flight booked with Air Canada may actually be operated by United Airlines through a codeshare agreement, allowing seamless connections between different carriers within an airline alliance. These agreements are common among major global airline networks like Star Alliance and Oneworld.

While codeshare flights provide more travel options, they can also lead to confusion over airline policies. The operating airline determines key services such as baggage allowances, check-in procedures, and onboard amenities. Travellers should check which airline is operating their flight to avoid surprises, especially when managing corporate travel. Working with a travel management company can help businesses navigate codeshare agreements and ensure employees book the most efficient and cost-effective routes.