Someone posted the lastest 757/767 retirements. Total shows 18 for next year. If all S80's would be retired it's another 42. Total of 60. Latest delivery schedule has 68(?) new jets next year. Some A320 retirements. I thorough the net total fleet change at one point was +/- 3 for the year.

Total projected 757/767 retirements for 2018-2020 in the list posted was 16. 2018 has 54(?) new deliveries. That would be offset by any additional A320 retirements and perhaps any early 737 (21 yrs old so still have useful life left) retirments.

Based on fleet dynamics and current orders I'd think that fleet expansion would start up again in 2019.