By using this possibility, carriers who do not operate their own aircraft on a given route may gain exposure in the market through display of their flight numbers.
In GDSs, Global Distribution Systems, such as Amadeus, Apollo, Worldspan, etc, this results in the same flight details, except for the flight number, being displayed on computer screens excessively forcing other airlines flights to be displayed on following pages where they may be missed by passengers searching for required flights.
Criticism has been levelled against code sharing by consumer organisations and national departments of trade since it is claimed it is confusing and not transparent to passengers but without any success in changing the situation so far.