1. A computer implemented method for providing assertions in response to a travel item query, the method comprising: as implemented by one or more computing devices configured with specific executable instructions, receiving usage data reflective of user activity on a travel service, the user activity comprising a plurality of queries for travel items offered by the travel service; for a set of search criteria, determining, based at least in part on the usage data, a plurality of assertions, each of the plurality of assertions representative of a modified set of search criteria determined based at least in part on a previous action of at least one user taken in response to previously presented query results corresponding to the set of search criteria, and wherein each assertion of the plurality of assertions is selectable by an additional user to generate a new query based at least in part on the modified set of search criteria corresponding to each assertion; receiving, from a user computing device, a query corresponding to the set of search criteria; transmitting, to the user computing device, a display page including results of the query corresponding to the set of search criteria and the plurality of assertions associated with the set of search criteria; receiving selection of an assertion of the plurality of assertions by the user computing device, wherein the selection of the assertion corresponds to a user request to generate the new query based at least in part on the modified set of search criteria; generating the new query based at least in part on the modified set of search criteria; and transmitting results of the new query to the user computing device.