Want to use an e-reader in flight? Not so fast.

Airline passengers hoping to kill time with a tablet, iPod or gaming device during a flight this weekend are likely to be disappointed.

While the Federal Aviation Administration (FAA) this week announced passengers would be able to keep their electronic devices on from “gate to gate,” the airlines still have to receive clearance that their planes are safe to operate with the gadgets on.

{mosads}A few carriers this week said they would move immediately to get the agency’s OK, but it’s unclear how long the process will take.

The FAA has said that it does not expect all airlines to be fully compliant with the new electronics rules until the end of the year. The agency attributed the variance to “differences among fleets and operations.”

FAA Administrator Michael Huerta said this week that even when all is said and done, a small percentage of airplanes would still be ruled incompatible with electronic devices.

“The committee determined that most commercial airplanes can tolerate radio interference from portable electronic devices,” he said of the panel that reviewed the proposed rule change for most of the year.

“It’s safe to read downloaded materials like e-books and calendars and to play games,” Huerta said. “But, the committee found that in some instances of low visibility — about one percent of flights — some landing systems may not be proven to tolerate the interference. In those cases, passengers should be asked to turn-off devices. We agree with that recommendation and our guidance to airlines reflects that.”

Delta and JetBlue airlines said this week that they were moving immediately to qualify for the expanded electronic use, but other major airlines did not put out statements about the timing of the rule change.

Delta said on Thursday that its passengers could begin using electronics for the entire lengths of flights as early as Friday, pending the FAA’s approval.

“We appreciate the FAA’s collaboration with the industry to define a path for enabling the safe use of portable electronic devices below 10,000 feet,” Delta Senior Vice President of In-Flight Service Joanne Smith said in a statement. “The Delta team is committed to always working to make flying better and thanks to their efforts our customers are the first to be able to use their devices throughout their entire flight.”

JetBlue similarly vowed just hours after the FAA rules change to be the first airline to implement it.

“The rules have caught up with today’s technology,” JetBlue Chief Commercial Officer Robin Hayes said in a statement. “This new policy vastly improves our customers’ experience, and giving everyone a chance to be more connected is good for business.

“We intend to be the first commercial airline in the United States to allow gate-to-gate use of personal electronics devices. To support that goal, we began the certification process with the FAA today.”

Passengers who are not flying on those airlines might be in for a rude awakening if they reach for their tablets, however.

The FAA said that it was providing implementation rules for airlines immediately, but the agency said that it is still incumbent on the carriers to request permission for the change.

“The FAA is streamlining the approval of expanded PED use by giving airlines updated, clear guidance,” the agency said in a statement announcing the new rules.

“Airlines will evaluate avionics as well as changes to stowage rules and passenger announcements. Each airline will also need to revise manuals, checklists for crewmember training materials, carry-on baggage programs and passenger briefings before expanding use of [Portable Electronic Devices],” the FAA statement said. “Each airline will determine how and when they will allow passengers broader use of PEDs.”

Huerta said passengers would not be given carte blanche to use their electronics in any way that they want.

“I want to be clear that you still cannot talk on your phone during a flight,” he said. “The Federal Communications Commission governs cell phone use during flights, and the committee did not consider that issue.

“All devices should be in airplane mode,” Huerta continued. “However, you will be able to connect through Wi-Fi to an airplane’s wireless network if the airline provides the service. And you will be able to connect to Bluetooth accessories like a mouse or keyboard.”

Huerta added that passengers will still be expected to look up from their electronic devices long enough to pay attention to safety announcements from flight attendants.

“There’s one thing that won’t change,” he said. “Passengers must take a break from their devices, their music, or whatever they’re doing, and listen to the safety briefing before each flight. It could save your life in the event of an emergency.”