Good

<?php
include("systems/systems.php");

$PossiblePaths = array();
$PathCount = 0;

function PlanRoute($nextID, $targetID, $history = null, $depth = 0){
    global $Systems, $PossiblePaths, $PathCount;

    //NextID is the key for the next steps to be made off of.
    $potentials = $Systems[$nextID]["JumpsTo"];
    if(!empty($potentials)){
        if(!in_array($targetID, $potentials)){ //Not at end location, therefore try next location
            $history[] = $nextID;
            $depth++;
            if($depth < 9){
                foreach($potentials as $value){
                    if(!in_array($value, $history)){
                        $path = PlanRoute($value, $targetID, $history, $depth);
                        if(isset($path)){
                            $PathCount++;
                            $PossiblePaths[$PathCount] = $path;
                        }
                    }
                }
            }else{
                return;
            }
        }else{
            foreach($history as $SystemID){
                $Trip[] = $SystemID;
            }
            $Trip[] = $targetID;
            return $Trip;
        }
    }
}

$origin = 30000090; //Get starting point
$target = 30000011; //Get end point

echo "Planning jump route from ".$Systems[$origin]['Name']." to ".$Systems[$target]['Name']."<br><br>\n";
PlanRoute($origin, $target);

var_dump($PossiblePaths);
?>