An airship...like you want it to pass over all tiles, though inpassable without the airship?
Use this. You have to have an item eqipped, but I'm sure it could be editted so if the item is in the inventory then you can walk through walls. Note: It is called a ring, but it can be anything equippable.
#===============================================================================
# ** Debug Ring
#-------------------------------------------------------------------------------
# Author Icedmetal57
# Version 1.0
# Date October 16th, 2006
#===============================================================================
#
# Description
#-------------------
# If a certain item is equipped, the player will be able to walk through walls,
# as if they were in DEBUG mode, in the RMXP editor.
#
# Instructions
#-------------------
# Scroll down a bit to the ACCESS_ID_NUMBER, and change it to the id number of
# the accessory you wish to have this debug type property.
#
# Compatability
#-------------------
# Compatible with SDK.
# To make it compatible with non-SDK, just delete the SDK lines.
#
#-------------------------------------------------------------------------------
#------------------------------------------------------------------------------
# * SDK Log Script
#------------------------------------------------------------------------------
#SDK.log('Debug Ring', 'Icedmetal57', '1.0', 'Oct - 16 - 2006')
#------------------------------------------------------------------------------
# * Begin SDK Enable Test
#------------------------------------------------------------------------------
#if SDK.state('Debug Ring') == true
class Game_Player < Game_Character
ACCESS_ID_NUMBER = 107
def passable?(x, y, d)
# Get new coordinates
new_x = x + (d == 6 ? 1 : d == 4 ? -1 : 0)
new_y = y + (d == 2 ? 1 : d == 8 ? -1 : 0)
# If coordinates are outside of map
unless $game_map.valid?(new_x, new_y)
# Impassable
return false
end
# If debug mode is ON and ctrl key was pressed
if $DEBUG and Input.press?(Input::CTRL)
# Passable
return true
end
if $game_actors[1].armor3_id = ACCESS_ID_NUMBER and Input.press?(Input::CTRL)
# Passable
return true
end
super
end
end
#--------------------------------------------------------------------------
# * End SDK Enable Test
#--------------------------------------------------------------------------
#end
(i commented out the SDK lines, uncomment them if you use SDK)
And for the encounter difference, go on hbgames.org and search for Seph's Test Bed. There is an encounter control in there.