PHP Factory Method Pattern Implementation
$militaryJet = JetFactory::create( 'FighterJet' );
$privateJet = JetFactory::create( 'PrivateJet' );
$commercialJet = JetFactory::create( 'JumboJet' );


This is a Factory pattern.  I'm not sure that I'd call it the Factory method pattern.  Look at the Wikipedia example for C# -- this looks like the before version.  If you were doing the same thing as the after version here, you'd have 

$militaryJet = FighterJetFactory::create();
$privateJet = PrivateJetFactory::create();
$commercialJet = JumboJetFactory::create();


Where FighterJetFactory, PrivateJetFactory, and JumboJetFactory would all extend or implement JetFactory.  

The question here is why not just say 

$militaryJet = new FighterJet();
$privateJet = new PrivateJet();
$commercialJet = new JumboJet();


Given this example, you don't need any variation of the Factory pattern.  You could just create the objects directly.  As a general rule, you shouldn't look to use design patterns.  You should meet problems that can be solved by the design pattern.  You don't have a problem that needs a design pattern to solve.  

Example of a problem that needs a Factory pattern solution:  given a passenger count and a cargo weight, return an object representing a plane that is capable of carrying those passengers with that cargo.  

Example of a problem that needs a factory method solution:  define an interface for a plane and another that will allow you to create a plane object.  Give the interfaces to two partners.  Have one write a BoeingFactory that implements your factory interface and the other an AirbusFactory.  Both should return plane objects that implement your plane interface.