Pan is modal: it stays active until you right-click or select another command.
To constrain panning of any viewport to a single axis, hold down the
key. The pan is constrained to the axis you first move while the
key is down.
To accelerate panning, hold down the
key.
You can also pan by dragging in a viewport while pressing the middle button of a three-button mouse. This lets you pan without turning on the Pan button.
To pan a viewport:
or right-click. To pan a non-Camera viewport:
+P.
; Maya mode: Hold down
, then drag with
. To accelerate panning:
key as you pan. To constrain panning to a single axis:
key as you pan. The pan is constrained to the first axis you use.
If you drag vertically at first, the pan or orbit is constrained to be vertical; if you drag horizontally at first, the constraint is horizontal.