Newbie Alignment and subdivision question

[Fonte Boa]

Another approach. If i understood correctly your example and your attempt using Tools|Align|Axis, this is the way to align an object face to another object face in JUST an axis, and keeping the target object static.

( a ) Select the target face
( b ) Tools|Bounding Box|Save Bounding Box (*)
( c ) Deselect all
( d ) Select the object face you want align to saved Bounding Box
( e ) Tools|Bounding Box|Move to Saved BB|(choose an Axis)

Here is the video: