These are the requested exercises:
1# Count de number of lines in Python for each file (DONE)
2# Top 10 arrival airports in 2013 (DONE) a) Airports city names (DONE) b) Use Pandas (DONE)
3# Plot monthly searches for MAD, BCN and AGP (DONE) a) Use Pandas (DONE)
BONUS EXERCISE 1: Match searches with bookings (Teorical solutions proposed)
BONUS EXERCISE 2: Write a web service (Someday ^_^)