x.knit

R code

# Approximate locations as factors
f <- flights()
dest   <- factor(sprintf("%.2f:%.2f", f[,3], f[,4]))

# A table of destination frequencies
freq <- sort(table(dest), decreasing=TRUE)

# The most frequent destinations in these data
frequent_destinations <- names(freq)[1:10]

# Subset the flight data by destination frequency
idx <- dest %in% frequent_destinations
frequent_flights <- f[idx, ]

# Lat/long and counts of frequent flights
ll <- unique(frequent_flights[, 3:4])

# Plot frequent destinations as bars, and the flights to and from
# them as arcs. Adjust arc width and color by frequency.
globejs(lat=ll[, 1], long=ll[, 2], arcs=frequent_flights,
        bodycolor="#aaaaff", arcsHeight=0.3, arcsLwd=2,
        arcsColor="#ffff00", arcsOpacity=0.15,
        atmosphere=TRUE, color="#00aaff", pointsize=0.5)