Codesharing

Codesharing is a practice in the aviation industry where two or more airlines share the same flight route. In a codeshare agreement, one airline (the marketing carrier) publishes and sells tickets for a flight that is actually operated by another airline (the operating carrier). Passengers book under the marketing airline’s flight number, while the aircraft and crew are provided by the operating airline. For example, a flight marketed as AA123 may be operated by BA, with the actual service continuing under BA’s flight code.

How it works is coordinated through interline and alliance agreements. The operating carrier handles ground services, crew, and on‑board service, while the marketing carrier handles ticketing, branding, and frequent-flyer accrual. Tickets, reservations, and baggage handling are coordinated to offer a seamless travel experience, though rules for fare classes, mileage earning, and eligibility may vary.

Origins and scope: Codesharing grew in the late 20th century and expanded with global airline alliances such as Star Alliance, oneworld, and SkyTeam. It enables airlines to offer a broader network without operating additional aircraft, while giving passengers access to more destinations and smoother connections.

Benefits and limitations: Passengers gain greater destination options and potential mileage accrual across networks, while airlines extend market reach. Limitations can include schedule sensitivity, differences in service standards, potential changes in baggage routing, and occasional confusion over flight numbers or connections. Overall, codesharing remains a central mechanism for expanding network reach in modern air travel.