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We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-18 · 6 min read · Independent comparison
• eppfun Professional — biggest strength: a foldable, rotating dual 3.5mm plug design plus switchable aptX Adaptive / aptX LL / aptX HD / aptX / SBC codecs, so it adapts to both single-port and dual-port airline sockets and to a much wider range of 3.5mm sources.
• eppfun Professional — biggest trade-off: 12 hours per charge, and the codec switching is a manual double-click routine that only matters if your headphones support the same codec.
• Avantree Relay & SoundJet — biggest strength: up to 25 hours of playtime on one charge with Qualcomm aptX Adaptive handling the audio, which is the kind of runtime a long international itinerary actually needs.
• Avantree Relay & SoundJet — biggest trade-off: it is built for the airplane seat and not much else — Avantree states it is not compatible with TVs, hearing aids or musical instruments, and it will not pair with phones or tablets.
• Who each pick is for: eppfun Professional for the traveler who wants one adapter that also serves a TV, car or fitness equipment; Avantree Relay & SoundJet for the flyer who wants maximum battery and a fuss-free two-person movie setup.
The eppfun Professional (model AK3046E Pro) is a Bluetooth 5.2 transmitter built around one very specific problem: airplane seats. Its two 3.5mm plugs rotate and can be used together or singly, which is the detail that matters most. Traditional single-port seat sockets take one plug. The dual-port sockets common on international inflight systems take both. One adapter covers both cases, and the foldable socket means it stores flat instead of poking out of your bag.
Where it separates itself is flexibility. The transmitter handles aptX Adaptive, aptX LL, aptX, aptX HD and SBC, and you can manually switch between them by double-clicking the multifunction button. In practice, you only bother if your headphones support the same codec on the other end — otherwise the adapter matches to the highest specification automatically and you never touch it. If you own aptX HD headphones and care about higher-quality audio, or low-latency buds and care about lip-sync, having the choice is genuinely useful. Lights tell you which mode is active, so you are not guessing.
Beyond the plane, eppfun lists compatibility with 3.5mm audio devices generally: computers, cars, fitness equipment and onboard entertainment systems. Dual-stream transmission sends audio to two headphones at once, so a couple or two friends can share a screen. Battery is 12 hours per charge, which covers most flights but not the longest ones back to back. A 15-minute idle auto-shutdown protects the charge when you forget it.
Who should buy it: travelers who fly a mix of aircraft, want one adapter that doubles as a home TV or car transmitter, and own headphones whose codecs they actually know. Who should skip it: anyone who wants the absolute longest runtime, and anyone who would rather not think about codec modes at all.
The Avantree Relay & SoundJet R1 Bundle is a purpose-built airplane adapter, and it is unapologetic about that. Avantree's own feature list says it plainly: not compatible with TVs, hearing aids or musical instruments, and as a transmitter only it does not pair with phones or tablets. Read that as a feature rather than a limitation. There is nothing to configure, nothing to second-guess, and no chance of pairing it to the wrong device mid-flight.
Two things define it. First, runtime: up to 25 hours of wireless listening on a single charge. That is roughly double the eppfun's 12 hours, and it changes the trip math. A long international itinerary with a connection, plus the airport layovers in between, fits inside one charge without you hunting for a USB port at the gate. Second, the two-headphone pairing is the headline use case rather than an extra. Pair two Bluetooth headphones or two sets of AirPods at once and watch side by side — built for couples and travel partners.
Audio runs through Qualcomm's aptX Adaptive, which Avantree positions as balanced sound with dependable wireless performance. The input side is 3.5mm AUX, the output side is Bluetooth, and the unit is battery powered. That is the whole story: a cable into the seat, two pairs of headphones in the air.
Who should buy it: frequent long-haul flyers, couples and travel partners, AirPods and Bose owners who want a clean wireless upgrade for inflight screens and nothing more complicated than that. Who should skip it: anyone who also wants to transmit from a TV, car stereo or gym machine — for those sources you need the eppfun instead.
• Best battery life → Avantree Relay & SoundJet. Up to 25 hours per charge versus 12 hours on the eppfun.
• Best for long-haul and multi-leg trips → Avantree Relay & SoundJet. One charge covers an itinerary that would leave the eppfun needing a top-up.
• Best for mixed single-port and dual-port airline sockets → eppfun Professional. Its two 3.5mm plugs rotate and work together or separately.
• Best for use beyond the plane → eppfun Professional. It is listed for computers, cars, fitness equipment and 3.5mm audio devices generally; Avantree explicitly rules out TVs and instruments.
• Best for codec control → eppfun Professional. aptX Adaptive, aptX LL, aptX, aptX HD and SBC, switchable with a double-click if your headphones match.
• Best for a no-thinking setup → Avantree Relay & SoundJet. Qualcomm aptX Adaptive does the work and there is nothing to switch.
• Best for two people sharing a screen → a tie, with a caveat. Both transmit to two headphones at once; the eppfun gives you codec choice, Avantree gives you the longer runtime.
• Best for AirPods and Bose owners flying long routes → Avantree Relay & SoundJet. It is positioned around exactly that pairing.
In my opinion, the Avantree Relay & SoundJet R1 Bundle is the one I would buy for flying. Twenty-five hours on a charge against twelve is the difference between landing relaxed and landing with a dead adapter, and the two-headphone pairing is the single most useful thing an airplane transmitter can do. The eppfun Professional is the better object — rotating plugs, five codecs, and a second life on your TV and car stereo — so if you want one adapter for the plane and the living room, buy the eppfun and accept the shorter runtime. If you fly long and fly often, buy the Avantree. Check the current price on Amazon before you commit, since that is the one variable I cannot weigh for you.
FAQ
Yes. eppfun lists compatibility with 3.5mm audio devices including computers, cars and fitness equipment, and its plugs work with a TV's 3.5mm headphone jack. Avantree states its adapter is not compatible with TVs.
Yes. Both support dual-stream transmission to two Bluetooth headphones simultaneously, which is what makes them useful for couples watching the same screen.
Both use aptX Adaptive as their top-tier mode. The difference is control: the eppfun lets you manually switch between aptX HD, aptX LL, aptX Adaptive, aptX and SBC, while the Avantree handles it automatically via the Qualcomm chipset. If your headphones support a specific codec and you want to force it, the eppfun gives you that option.
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