u-back').on('click', function(){
      $('#results').addClass('hide');
      $('#menu').removeClass('hide');
    });

    // all the shenanigans used to determine whether or not the user
    // has picked the correct flight: the origin city, the desination city,
    // the date, and whether or not it's the cheapest/shorest flight.
    var correctOrigin = inputOrigin.indexOf(userOrigin) !== -1;
    var correctDestination = inputDestination.indexOf(userDestination) !== -1;
    var correctDate = inputDate === 