I am looking for a weekend MR for AA miles, I am HEL based and AY flights suit my plan well. Was happy to see that there are ex-ARN flights to LAX for ~550€ and you have to stay in LAX for only 9 hours (Sat 2203 - Sun 0700). ARN-HEL-JFK-LAX-JFK-HEL-ARN (+ positioning HEL-ARN rt) will net a nice 15184 EQM on AA, available on AA-codeshare (excl. positioning) so this might be also good for AY Plus?
Any risk positioning with the same plane that starts the MR if travelling without checked luggage? Are they able to check you in for all flights at HEL if the ARN-HEL-JFK-LAX is AA-codeshare?