Travel agents may also work with airline consolidators. Many consolidators also act as host agencies for local travel agencies. Billers, bankers, aggregators and consolidators can play various roles in the overall process. Even though many consolidators are online, most consolidators still work only through retail travel agents. Consolidators most commonly operate in international markets. Allcargo through its wholly owned subsidiary, ECU-LINE acquired Econocaribe Consolidators, a US based logistics company. At the same time, Cheapflights started as a listing service for flight deals from consolidators. This process is also known as zone skipping, long used by Parcel Consolidators. The consolidators ran into unexpected opposition, however, from President Theodore Roosevelt.