Britain suspended flights to Sharm el-Sheikh after saying it feared a bomb may have brought down a Russian jet shortly after it took off from the Red Sea resort last week, killing 224 people, and that security at the airport was lax.
"What we've got to do is ensure that... Airport security reflects local conditions," Philip Hammond told the BBC on Sunday.
"Where there's a local higher threat, that will mean higher levels of security are required and that may mean additional costs and may mean additional delays at airports."
"If this turns out to be a device planted by an IS operative, or by somebody inspired by IS, then clearly we will have to look again at the level of security we expect to see in airports in areas where IS is active," Hammond said.
The decision to suspend flights with immediate effect came after a team of British security experts made an initial security assessment in Sharm el-Sheikh, but the government has yet to identify IS as the perpetrators.
"The ambassador is telling me that the mood in Sharm is generally calm, people understand what is going on," he told the BBC.
"Many people will want to stay and complete their holiday," he added. "At most people will experience a delay of two or three days.
