To sum it up: Now 42 - 47 in 2017. Capacity at SPIRIT is higher.
and here is the outcome: In August, Boeing Chief Financial Officer Greg Smith indicated that Boeing is close to deciding whether to push 737 production to 52 a month.
Increasing the production rate is a benefit to Boeing and to airlines, since it allows the plane maker to offer airlines the chance to buy planes sooner, rather than putting their orders at the end of its order book.
Exactly my view - simply looking at AB order book 46/month in 2016 is NOT ENOUGH.
Both airframers give advance notice to their suppliers, because the main problem is their capacity to implement the changes at the set date. A very precise process exists, but Airbus makes sure, ahead of any change, that suppliers can execute. I guess Boeing does just the same.