Assuming that you want to so something(remove Arrival) on each of the values, you can use this:
<?php
$results = array (
'date' => '22. jan.',
'flightNumber' => 'EZY6747',
'airline' => 'easyJet',
'from' => 'Belfast International',
'plannedArrival' => '18:35',
'realArrival' => 'Estimated Arrival 18:32'
);
$result2 = array_map(function($s)
{
return str_replace('Arrival ', '', $s);
}, $results);
print_r($result2);
solved PHP Strip specific keys in array