1. Commercial aerospace Boeing Reduce CO2emissions Electrification 2014-2019 [1]
2. Airbus Reduce CO2emissions Electrification 2014-2019 [2] Siemens' E-fan, now
3. Reduce CO2emissions Hybrid-electric 2015-2019 [3]
4. GE Reduce CO2emissions Hybrid-electric 1980, 2008 [4]
5. http://www.boeing.com/features/2012/05/sugar-volt-boeing-hybrid-electric-aircraft-05-2-12.page