The U.S. government said Friday it is taking additional security measures after seizing two explosive packages packed aboard cargo jets, which could mean more hassle for travelers this weekend.

Even though the packages addressed to Chicago-area synagogues were on cargo jets, airline passengers will see stepped-up security, too. Federal officials warned that they were not assuming that the two packages they found were the end of the attack.

The Department of Homeland Security said it has “taken a number of steps to enhance security,” some visible, some not.

It said travelers should expect “heightened cargo screening and additional security at airports” including the detection of trace amounts of explosives, bomb-sniffing dogs, and pat-downs.

Delta Air Lines Inc. confirmed that it is increasing security in response to the incident, though it didn’t provide details. All airlines carry cargo in the bellies of their passenger planes.

Delta and United Continental Holdings Inc. both said their flights to Dubai and other points in the Middle East would go forward as planned on Saturday.

Over the long run, the incident is not likely to result in any major security changes that passengers will see, said Jim Ramsay, a professor and coordinator of the homeland security program at Embry-Riddle Aeronautical University.

The U.S. has known all along that cargo — especially cargo from overseas — is a risk, he said.

“It was possible yesterday. It was discovered today,” he said.

The international cooperation that foiled the plot on Friday is a sign that the U.S. is working well with allies to stop attacks. And as long as there is air travel, there will be risk, he said.

“Commerce needs to continue,” he said. “Passengers are not at any more risk now than they were before.”