Max size for Carry-On laptop bag / messenger murse?

[zan5hin]

Hi, I am going away for 2.5 months in May-July and only taking a carry-on as it will be hot. Mostly Cebu city, but also Manila, Taiwan, Singapore and KL.

So I will only be taking my Osprey 35L backpack and loading it to 7kg, but the airlines let you take a second bag, as long as it slides under the seat in front I have read. But I am wondering just how big this second bag can be?

I know the weight limit will be 3kg but there is no firm info about dimension limits. I would like something that can fit at least my new iPad, but also 12.1" (my current laptop) but possibly a 13.3" ultrabook when I upgrade.

Anyone have experience with being stopped for having something too big as your second carryon?

I am booked to fly Jetstar, Cebu Pacific and Scoot airlines and I might throw Air Asia in the mix too.

Also, anyone got a tip on a decent messenger bag with a comfortable shoulder strap, preferably some water resistance too, that I can buy online?

Cheers

 

[serfty]

Some airline provide guidelines for maximum size for your laptop bag.

e.g. AA: "Personal item - includes: purse, briefcase, laptop bag OR a similar item such as a tote that does not exceed 36 inches( length+width+height) and must fit under the seat in front of you."

Have you checked the websites of the airlines operating your flights?