Oil prices fell more than $2 a barrel yesterday as thwarted airplane attacks led many carriers to cancel flights, which could mean dampened jet fuel demand and weaker consumer confidence.

Prices also deflated after Shell announced it was bringing back 180,000 barrels of daily oil production in Nigeria. Goldman Sachs, meanwhile, said it would end its participation in the New York Harbor unleaded gasoline contract, as expected, but wouldn’t roll its money into another contact.

Gasoline prices fell 9% to a four-month low, as big funds bailed out of the contract.

Yesterday, British authorities said they had stopped a terrorist plot to blow up several aircraft in flight between America and Britain.

European carriers canceled flights to Britain, where airports were experiencing massive delays. There were delays in America, too, amid heightened security.

Tom Bentz, an analyst at BNP Paribas Commodity Futures in New York, said the news “revives fears, and causes people to cut travel plans, which has a contracting effect on petroleum demand.”

Light, sweet crude for September delivery dropped $2.35, or more than 3%, to settle at $74 a barrel on the New York Mercantile Exchange — erasing all of this week’s gains, and more. It was the lowest settlement price since July 28.

Gasoline futures dropped 18.33 cents to finish at $1.9889 a gallon, the lowest it’s settled since finishing at $1.9766 on April 7.

Heating oil futures fell 8.13 cents to settle at $2.0250 a gallon.

Brent crude on London’s ICE futures exchange fell $2 to settle at $75.28 a barrel.

Yesterday, a Nigerian pipeline run by Royal Dutch Shell PLC was back in service, according to Dow Jones Newswires. Shell had blocked the 180,000 barrel-a-day pipeline in late July after an unexplained leak.

Southern Nigeria, where most of the nation’s crude is pumped, has seen violence against the petroleum industry rising. Kidnappings and attacks have forced a cut of about 20 percent of Nigeria’s usual 2.5 million barrel daily production.

Also yesterday, Goldman Sachs announced it would not be rolling over its remaining positions in the New York Harbor Unleaded Gasoline contract, which is being phased out because the American government has labeled ingredient MTBE as a pollutant.

“The big players are getting out of it … with Goldman Sachs getting out, it’s the final nail in the coffin,” said Phil Flynn, Alaron Trading Corp. analyst, noting that big funds are increasingly trading Nymex’s more environmentally friendly gasoline contract, the Reformulated Gasoline Blendstock for Oxygen Blending futures contract.

Prices continued to be affected by supply disruptions in Nigeria due to civil unrest; BP’s Alaskan pipeline being shut down because of corrosion; the standoff between the United Nations and Iran over the nuclear program of OPEC’s no. 2 oil producer; and fighting in the Middle East between Israel and Hezbollah.