I haven't traveled with clubs in a long time, but I have an opportunity coming next month.  In the past I used a simple canvas bag with my own improvisations - like lots of towels for padding and a homemade version of a "stiff arm" to protect the shafts. 
I like my clubs much more these days :) and want better protection.  I assume a hard case would provide better protection, but could be a challenge to fit into a rental car.  Is it safe to travel with today's soft travel cases like the Titleist club glove travel cover?
Thanks.