If you want a clear sign that Apple is serious about eventually offering consumers a car, then look no further than Doug Field who has just rejoined the company after spending five years at Tesla.

As Daring Fireball reports, Apple spokesperson Tom Neumayr confirmed that Field is indeed employed by Apple once again and he's working with Bob Mansfield on Project Titan, which is Apple's car project. This is significant for a couple of reasons.

Doug Field is a very experienced engineer, having enjoyed spells at Segway from 1999 to 2008 as VP of design and engineering as well as becoming the company's CTO. Then Field joined Apple in mid-2008 as VP of product design before moving to become VP of Mac hardware engineering in 2011. He then left to join Tesla in 2013 and has spent the last five years overseeing engineering with a particular focus on the Model 3.

So what we have now is someone who is already experienced working within Apple who went off and got five years experience at the most successful electric car company in the world so far. Now he's brought that experience back to Apple and is focused on the iPhone maker's car project.

Is Elon Musk going to be upset by this? Quite possibly, but it's to be expected in such a competitive, new, and growing market. What exactly Project Titan ends up being... an autonomous driving system or a complete car... is anyone's guess right now, but Field returning to Apple suggests the company is still considering manufacturing its own vehicles. That fits with what Apple does: produces all its own hardware and sells them directly to consumers.