Dude, the only way is to have: jetparts, wingparts and bordparts, Go to Sharoarea, get to the lower parts, pay 500 zeny and talk to orange navi, she will give instructions.

Signed, The Cheat Guru.

go to yumland and find a evil navi, go to town area 3 (bottom) and town area 2 bottom
(hiding)

are one in town are 3 in the part under te floor of town area 3 the another is in town
area 2 hidden down a path and the other yumland hidden under the stairs i think that this
help you ok:)