diff --git a/README.md b/README.md
index 0c93046..ceb8ddc 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,8 @@ See [`methodology.md`](./methodology.md) for details of what it does and where d
 It is supported by an S3 Blob storage container for caching data, thereby
 reducing its impact to [https://adsbexchange.com/](https://adsbexchange.com/).
 
+![Design](./design.drawio.png)
+
 ## Risk and impact
 
 This code performs API calls to [https://adsbexchange.com/](https://adsbexchange.com/),
diff --git a/design.drawio.png b/design.drawio.png
new file mode 100644
index 0000000..141b69b
Binary files /dev/null and b/design.drawio.png differ
diff --git a/methodology.md b/methodology.md
index c1d56db..a14e740 100644
--- a/methodology.md
+++ b/methodology.md
@@ -233,40 +233,3 @@ constraints:
 ```
 
 Source code is available at [src/bin/etl_legs.rs](./src/bin/etl_legs.rs).
-
-### M-emissions-private-jet: Emissions of a private jet over a leg
-
-This was performed automatically by the program and consisted in the following calculation:
-
-```
-leg emissions [kg CO2e] = 
-  consumption [gallon/h]
-  x liters / gallons [L/gallon]
-  x liters to kg of jet fuel [L/kg]
-  x emissions per kg [kg CO2 / kg jet fuel]
-  x Radiative Forcing index [kg CO2e / kg CO2]
-  x Life-cycle emissions [kg CO2e / kg CO2e]
-  x leg time [h]
-```
-
-Where:
-
-* `consumption` is obtained via the methodology `M-6` in this document.
-* `liters / gallons = 3.78541 [L/gallon]`, as specified in [NIST's guide to SI](https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication811e2008.pdf)
-* `liters to kg of jet fuel = 0.8 [kg/L]`, as [recommended by ICAO](https://data.icao.int/newDataPlus/content/docs/glossary.pdf)
-* `emissions per kg = 3.16 [kg CO2 / kg jet fuel]`, as used on [ICAO Carbon Emissions Calculator Methodology, v12 from Sep. 2023](https://applications.icao.int/icec/Methodology%20ICAO%20Carbon%20Calculator_v12-2023.pdf)
-* `Radiative Forcing index = 3 [kg CO2e / kg CO2]`, as concluded in [The contribution of global aviation to anthropogenic climate forcing for 2000 to 2018](https://www.sciencedirect.com/science/article/pii/S1352231020305689), from 2021.
-* `Life-cycle emissions = 1.68 [kg CO2e / kg CO2e]`, [Life Cycle Greenhouse Gas Emissions from Alternative Jet Fuels v1.2](https://web.mit.edu/aeroastro/partner/reports/proj28/partner-proj28-2010-001.pdf) from 2010-06, accessed 2024-01-28.
-* `leg time [h]` is obtained by computing duration of the leg, as identified via the methodology `M-identify-legs` in this document.
-
-#### Per passager
-
-```
-leg emissions/person [kg CO2e/person] =
-  leg emissions [kg CO2e]
-  x occupancy [1/person]
-```
-
-where
-* `leg emissions [kg CO2e]` is as computed above
-* `occupancy = 0.23 [1/person] = 1/4.3 [1/person]` obtained from [Average number of passengers per flight who flew private worldwide from 2016 to 2019](https://www.statista.com/statistics/1171518/private-jet-per-flight/), where there were 4.3 passagers per flight in 2019, accessed 2024-01-28.
diff --git a/src/bin/etl_legs.rs b/src/bin/etl_legs.rs
index 28df5c1..fc002ec 100644
--- a/src/bin/etl_legs.rs
+++ b/src/bin/etl_legs.rs
@@ -6,10 +6,15 @@ use std::{
 
 use clap::Parser;
 use futures::{StreamExt, TryStreamExt};
+use itertools::Itertools;
 use serde::{de::DeserializeOwned, Serialize};
 use simple_logger::SimpleLogger;
 
-use flights::{aircraft::Aircraft, fs::BlobStorageProvider, Position};
+use flights::{
+    aircraft::{Aircraft, Aircrafts},
+    fs::BlobStorageProvider,
+    Position,
+};
 
 static DATABASE_ROOT: &'static str = "leg/v2/";
 static DATABASE: &'static str = "leg/v2/data/";
@@ -192,7 +197,7 @@ async fn etl_task(
 }
 
 async fn aggregate(
-    required: HashMap<(Arc<str>, time::Date), Arc<Aircraft>>,
+    required: HashMap<(Arc<str>, time::Date), Aircraft>,
     client: &dyn BlobStorageProvider,
 ) -> Result<(), Box<dyn Error>> {
     let all_completed = list(client).await?;
@@ -261,6 +266,26 @@ async fn aggregate(
     Ok(())
 }
 
+async fn private_jets(
+    client: &dyn BlobStorageProvider,
+    country: Option<&str>,
+) -> Result<Aircrafts, Box<dyn std::error::Error>> {
+    // load datasets to memory
+    let aircrafts = flights::aircraft::read(time::macros::date!(2023 - 11 - 06), client).await?;
+    let models = flights::load_private_jet_models()?;
+
+    Ok(aircrafts
+        .into_iter()
+        // its primary use is to be a private jet
+        .filter(|(_, a)| models.contains_key(&a.model))
+        .filter(|(_, a)| {
+            country
+                .map(|country| a.country.as_deref() == Some(country))
+                .unwrap_or(true)
+        })
+        .collect())
+}
+
 #[tokio::main(flavor = "multi_thread")]
 async fn main() -> Result<(), Box<dyn Error>> {
     SimpleLogger::new()
@@ -275,8 +300,27 @@ async fn main() -> Result<(), Box<dyn Error>> {
     let client = &client;
 
     log::info!("computing required tasks...");
-    let required =
-        flights::private_jets_in_month((2019..2025).rev(), maybe_country, client).await?;
+    let private_jets = private_jets(client, maybe_country).await?;
+
+    let months = (2019..2024)
+        .cartesian_product(1..=12u8)
+        .map(|(year, month)| {
+            time::Date::from_calendar_date(year, time::Month::try_from(month).unwrap(), 1)
+                .expect("day 1 never errors")
+        })
+        .collect::<Vec<_>>();
+
+    let required = private_jets
+        .into_iter()
+        .map(|(icao, aircraft)| {
+            months
+                .clone()
+                .into_iter()
+                .map(move |date| ((icao.clone(), date), aircraft.clone()))
+        })
+        .flatten()
+        .collect::<HashMap<_, _>>();
+
     log::info!("required : {}", required.len());
 
     log::info!("computing completed tasks...");