After a quick search, it seems that Air 2 still has 1GB of RAM

http://www.devicespecifications.com/en/comparison/213211f3b

http://www.phonearena.com/news/Apple-iPad-Air-2-vs-Google-Ne...

If more apps on Air 2 are 64-bit than on Air 1, the memory consumption with Air 2 would be more than that with Air 1. In case the RAM size stays the same, Air 2 could see more page-in/page-out, especially when you keep lots of chrome tabs open or other tasks on...

But perhaps different user groups have different usage patterns that fit different hardware configuration, and Apple might know it very well...