UPDATE 1-Boeing 737 deliveries rebound in August to 48, from 29 in July

(Adds detail on production snarl)

Sept 11 (Reuters) - Boeing Co said on Tuesday it delivered 48 of its best-selling 737 single-aisle aircraft in August, bouncing back from the 29 it delivered in July, the fewest in years.

Deliveries at the world's biggest planemaker have been delayed as unfinished aircraft pile up at its Renton, Washington plant as a result of production bottlenecks at its suppliers.

Boeing's 737 and Airbus' A320 family of single-aisle aircraft are the cash cows of the two companies, the world's largest aircraft manufacturers.

While monthly delivery figures can fluctuate, the numbers give a snapshot of how far behind Boeing is delivering planes against its production of 52 narrowbodies per month. Deliveries are crucial to planemakers because that is when airlines pay most of what they owe for the aircraft.

The snarl at its plant in Renton, Washington, triggered by shortages of engines and fuselages as Boeing sped production to record levels in June, is likely to hurt third-quarter results and threatens its goal to boost build rates again in 2019, some analysts said after meetings in the Seattle area last week.

Boeing largely attributes the snarl to shortages of fuselages from Wichita, Kansas-based Spirit AeroSystems Inc and engines from CFM International Inc, a venture of France's Safran and General Electric Co.

Total plane deliveries fell to 64 in August, from 66 units a year earlier, and 39 units in July.

(Reporting by Ankit Ajmera in Bengaluru; Editing by Shounak Dasgupta)