LE BOURGET, France — Boeing Co. finally joined the orders race on the third day of the Paris Air Show, but its $153 million order Wednesday for two single-aisle planes paled beside the $6.25 billion already chalked up by European rival Airbus.

Yet even Airbus’ numbers were diminutive compared to sales in past years. Airlines and governments strapped for cash and credit appeared to have come to the world’s biggest air show as tourists instead of buyers this year.

The vast bulk of the commercial orders have been for single-aisle planes, the cash cows of both Boeing and Airbus. In the current economic climate, it’s harder for airlines to finance larger aircraft, which may also be harder to fill if the recession continues to dent air travel.

Boeing won its first order Wednesday — small but a symbolic breakthrough — for two of its updated 737-800 jets from aircraft leasing company MC Aviation Partners.