in search request page: 
date_default_timezone_set("UTC"); 
$casodletu= date("H:i:s", time()); 
<td>Select Departure time:</td> 
			<td> 
				<select class="search" name="deptime"> 
					<?php 
							{echo '<option value="'.$casodletu.' selected">Upcoming</option>';} 
							{echo '<option value="">All</option>';} 
					?> 
				</select> 
			</td> 
in FrontSchedulesData class 
insert in function findschedule 
	 public function findschedule($arricao, $depicao, $airline, $deptime)   { 
		$query = "SELECT phpvms_schedules.*, phpvms_aircraft.name AS aircraft, phpvms_aircraft.registration 
				FROM phpvms_schedules, phpvms_aircraft 
				WHERE phpvms_schedules.depicao LIKE '$depicao' 
				AND phpvms_schedules.arricao LIKE '$arricao' 
				AND phpvms_schedules.code LIKE '$airline' 
				AND phpvms_schedules.deptime > '$deptime' 
..... 
this will show for you departure after current GMT time.  
Other (your modification of FrontSchedules.php is good).