It’s been a busy week in the world of exchange traded funds (ETFs) and exchange traded notes (ETNs), bringing us a new provider, a first for an existing one and two new offerings from another.

Direxion, known for its leveraged and inverse ETFs, launched the Direxion Airline Shares ETF (NYSEArca: FLYX), its first non-leveraged ETF. FLYX is based on the NYSE Arca Airline Index and touts a 0.65% expense ratio. The fund joins one other ETF that tracks the same sector, Guggenheim Airline (NYSEArca: FAA), which has almost $39 million in assets since its launch in January 2009. [Giving the Airline ETF a Pat Down.]

Oliver Ludwig for Index Universe reports that despite the existence of another airline ETF, it’s  an opportunity to fill a space that is quite empty. Other indicators that the airline industry is ready for takeoff:

ProShares today launched a long/short ETF that delivers long and short exposure to an index that eschews traditional market-cap weighting methods and instead ranks stocks by fundamental factors. ProShares RAFI Long/Short ETF (NYSEArca: RALS). The fund is based on strategies developed by the “father of fundamental indexing,” Rob Arnott.

Murray Coleman at Barron’s explains how it works: stocks are selected on four valuation measures. The best positions will go long, the worst shorted. Long and short positions will be equally weighted, so the fund will be neutral to market swings.

RBS Securities, which is a unit of the Royal Bank of Scotland, launched its first ETN for U.S. investors. The fund is linked to the S&P 500, but it contains downside protection in the event that the markets turn south.

The RBS U.S. Large-Cap Trend Pilot ETN (NYSEArca: TRND) tracks the firm’s proprietary index. It returns either the performance of the S&P 500 Total Return index or the yield of three-month Treasuries, depending on how the S&P is doing, say Steve Dew and Olivier Ludwig for Index Universe.

As long as the S&P is above its 200-day moving average, investors will earn S&P returns. If it drops below for five days, the exposure shifts to Treasuries.

Tisha Guerrero contributed to this article.