Airplane mode -- can't view Mail attachments

Hello friends,

Before I upgraded to iOS 9, Mail kept a local copy of attachments to messages which are in my IMAP mail account. This was really handy if I wanted to read an attachment if I was on an airplane flight. Now it seems Mail will no longer do this as I have no access to attachments without network connectivity. Anyone know why in the world Apple would have done this or am I missing some setting that I can't find that would allow offline access to attachments? Thanks.