An airline consolidator (sometimes called a bucket shop) is a specific kind of airline ticket

Airline ticket

An airline ticket is a document, issued by an airline or a travel agency, to confirm that an individual has purchased a seat on a flight on an aircraft. This document is then used to obtain a boarding pass, at the airport...

 reseller. Consolidators work through contracts with major carriers to manage blocks of airline seat

Airline seat

An airline seat is a chair on an airliner in which passengers are accommodated for the duration of the journey. Such seats are usually arranged in rows running across the airplane's fuselage...

 inventory at reduced prices which they then sell. The main benefit being that fares through consolidators will be lower than published rates available from the airlines themselves. Airlines consolidators do not buy the seats in bulk for resale, they sell the available inventory at contracted rates.