The deals underscore the growing importance of the huge commercial aviation market in the Asia-Pacific region.
"Boeing is serious about helping customers optimise performance of their fleets and reduce operational costs," said Stan Deal, president and chief executive of Boeing Global Services.
Among the deals is an agreement with Malaysia Airlines to receive overhauled landing gear from an exchange pool maintained by the US aviation giant.
Singapore Airlines signed a contract to use electronic logbooks on its Boeing 777 and 787 airliners.
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Its European rival Airbus said Tuesday that air traffic will triple in the Asia-Pacific region over the next 20 years, making it the world's biggest aviation market.
The region will require 14,450 new aircraft during that period, worth a combined $2.3 trillion.
This accounts for more 40 percent of global demand, Airbus said.
The Singapore Airshow, the biggest such event in Asia, is held every two years.
Analysts say they do not expect major plane orders at this year's show.