In March 1953, the Indian Parliament passed the Air Corporations Act to streamline and nationalise the then existing privately owned eight domestic airlines into Indian Airlines for domestic services and the Tata group-owned Air India for international services.[197] The International Airports Authority of India (IAAI) was constituted in 1972 while the National Airports Authority was constituted in 1986. The Bureau of Civil Aviation Security was established in 1987 following the crash of Air India Flight 182.

You can make money whichever way floats your boat. I got a lot of slack in this post for trading forex, but I live in one country, and need currency from three other countries where I own property and travel to often, so when one currency is cheap, I do take advantage of fluctuations. It may not be your thing, but the important part is that you have more than one source of income.
I prefer assets that make me a high return for the lowest amount of work possible (semi-passive involvement). And assets that pay me in several unique ways. Cash flow is only one way RE makes money for me. I also get principal reductions, appreciation, tax advantages (depreciation), and I control the rental increases on a yearly basis. Plus a majority of the capital is provided by the secondary market on 30 year fixed low interest rate debt.
This is a buzzword I heard about through a few career coaches. Slowly more awareness is spreading that we can escape the rat race and find alternative ways of working, and indeed, the days of having to choose one particular career path are becoming outdated. The recession is forcing us to think of more imaginative ways to make a living and I am determined to use every skill and talent I have to start generating multiple income streams. Before I was racking my brain for YEARS because I just couldn’t choose one career path! I am only just beginning on a small scale and am not making any real money as yet, but this year I will dig out the toolboxes I’m not currently using and set up various things that will hopefully bring in the pounds. Thumbs up to multiple income streams.
Why did P2P lending get a liquidity ranking of 6? It is quite possibly the most illiquid investment option you listed. You said you rank liquidity by “difficulty level of withdrawing your money without a massive penalty”, and for Lending Club notes, it’s not only difficult and extremely time consuming to sell all of your notes in their super illiquid market, but you would have to sell your notes at large losses to hope to get others interested in buying your notes. On top of that, it is impossible to withdraw your money any other way other than just waiting for interest/principal to pay off every month until maturity in 3 to 5 years. You can’t just one day tell Lending Club “I want to quit, please give me my money back.” One can even argue that it is less difficult to sell a home (in order to “withdraw” the money invested) than to withdraw all of their money from a P2P loan portfolio because it is very possible to sell a home before 3 to 5 years.

While it is important to find something that you love to do and turn it into a money making business, you do have to be cognizant of the return as you pointed out. There are many opportunities that I found and tried out that at the time seemed great. But when I took a step back, I realized that I was working a lot for very little income whereas other things I love doing brought in much more money.
Retirees are paying a high price as the world stimulates its way out of the GFC (Great Recession).  After a 30-year bull market to the lowest interest rates the world has ever seen, bonds have become highly priced and now don’t generate enough to meet income needs.  Just 5 years ago the average income from $100,000 invested in a 10 year Australian Government Bond (10yrs) was $5,600 p.a.  – now it’s less than half at $2,600 p.a.