The 10th anniversary of Concorde's last flight sadly means it's been 10 years since your average (albeit wealthy) Joe could travel faster than the speed of sound. Although Concorde isn't going to be taking off any time soon, these supersonic concepts might fill that sonic-boom sized hole in your heart -- and for a damn sight cheaper, too.
Unless you spent this year hiding under in a lead-lined cave, you probably heard that eccentric PayPal founder Elon Musk has invented a whole new mode of transport call the Hyperloop, which is kind of like a maglev train that runs in a vacuum. Of course, he's too busy building electric cars and taking 3 per cent of our money in fees to actually build the damn thing, so he's just released the plans to the general public instead.
Basically, Hyperloop uses a low-pressure tube (not a vacuum), with 'pods' carrying passengers through. The pod floats on a cushion of air, just like an air-hockey puck, and the initial acceleration (and braking) comes from electromagnets.
Although the original proposed use was as a shuttle between New York and San Francisco, one far more interesting proposed application is as a line under the ocean. This solves one of the main problems with the Hyperloop problem (it has to go in a pretty much perfectly straight line), and, because Hyperloop takes most of its energy to simply accelerate, the longer the distances it travels, the more efficient it is.
That said, whereas an above-ground Hyperloop failure might just lead to a few brown-trouser incidents, I can't imagine a breakdown a few miles under the ocean being particularly healthy.
Lear Jet? Pathetic. If you're a high-rolling multi-billionaire, you want to be on the pre-order list for just one thing (and it's not a PS4). Aerion is well advanced on designing a supersonic business jet, capable of carrying a handful of passengers in style at Mach 1.7. The aim is to be able to fly from London to North America and back again in the space of a day -- handy if Skype's down, I suppose.
Aerion's breakthrough technology is supersonic natural laminar flow, which reduces the noise of flying supersonically, as well as bringing down drag (and thus fuel costs). Although no prototype aircraft have been built yet, the aerodynamics have been proven with test flights on NASA aircraft, which seems to be enough to persuade investors: according to Aerion, 50 different people have slapped down $250,000 deposits.
A scramjet is a unique type of engine that allows combustion of air travelling at supersonic speeds -- unlike normal jets, which generally reduce the airflow to subsonic speeds. Scramjets operate efficiently at ridiculously high speeds -- we're talking around Mach 20 here; however, getting to those speeds is impossible for a scramjet alone, which means they require help to get up to pace.
Although there are no passenger scramjet-powered aircraft currently under development, there's at least a working prototype. The X-51 Waverider is a US Air Force prototype that's successfully flown a handful of times now, reaching over Mach 5 (before crashing into the ocean in a fiery wreck).
The most obvious replacement for Concorde is, well, Concorde 2.0. One of the big problems with Concorde was that the sonic boom pissed a lot of people off, so that flight over land was prohibited in dozens of countries, removing a bunch of potentially profitable routes for British Airways and Air France.
As such, the designs for next-gen supersonic aircraft being considered by NASA at the moment put the focus on removing the sonic boom. Designs from Boeing and Lockheed Martin make use of advancements in aerodynamics and wing design to minimise the sonic boom and maximise fuel economy. Sadly, with no design on the drawing board yet, flights are at least ten years away -- by which time we'll have probably burned up all the jet fuel anyway.
The plucky British entrant in the supersonic travel category, Skylon is an awesome Space Shuttle replacement that has a double-function engine that can work in both the atmosphere and in space, meaning that the plane can launch, orbit and land without the need for booster rockets a la Space Shuttle (or the Virgin Galactic thing).
Operating at speeds in excess of Mach 5.5, and capable of getting into orbit, there wouldn't really be anywhere on Earth that Skylon couldn't reach inside of a few hours. As it stands, the engine (the real technical innovation of the project) is currently in the prototype stage, with the first test flights expected around 2020.